apo-wiki

Attending: Nancy Chanover (NMSU), Sarah Tuttle (UW), Joanne Hughes (Seattle U), Bill Ketzeback (APO), Michael Hayden (OU), Eric Bellm (UW), Moire Prescott (NMSU), Aleksandr Mosenkov (BYU), Ben Williams (UW), Misty Bentz (GSU), Kevin Schlaufman (JHU), Anne Verbiscer (UVa)

• NMSU - nothing to report other than users are eager to hear about KOSMOS updates
• Washington - nothing to report other than users are eager to hear about KOSMOS updates
• UVa - nothing to report
• Colorado - no report
• BYU - nothing to report
• Georgia State - nothing to report
• Oklahoma - nothing to report other than users are eager about KOSMOS updates
• Wyoming - no report
• JHU - nothing to report
• Seattle - nothing to report
• Colgate - no report
• Williams - nothing to report (by email)

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 10/08/25 – 12/02/25

1) Overview

This report spans two months, as the November meeting was cancelled due to its conflict with the ARC Board of Governors meeting.

The first half of October experienced very unsettled weather, while the second half of the month through the middle of November had beautifully clear skies. The latter part of November again was nearly weathered out, and we saw our first light snowfalls of the season.

We had three class visits during this time period: (NMSU) mid-October, (UVa) end of October, and (Colgate) mid-November. Russet McMillan and Amanda Townsend are currently sharing training responsibilities. We had a visiting PI Instrument observing run early in November.

2) Operations

3.5m Telescope: Telescope is working as expected. Seasonal motion errors continue to occur infrequently. We anticipate that some tuning of the axis drives will be necessary soon with the cooling weather. The failures have not increased as expected so far. There was an instance of a motor amplifier fault on the tertiary mirror actuator in mid-October. It was corrected by homing the mirror and restarting the mirror controller software.

0.5m Telescope: Telescope is working as expected. Dcam-spare and UVAcam are both available options for users. Additional testing of BYUcam was performed during some available engineering time. The water spots were cleaned from Dcam-spare, and the chamber repressurized with gaseous nitrogen.

KOSMOS: System is cold and stable. Repaired the cold strapping and reassembled the cryostat near the end of October. A month later, we experienced dewing on the cryostat window, which was dried and waterspots cleaned using purge air.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. There was an instance where the controller locked up, making exposures impossible. Resetting led to a quadrant drop. Recovery was not as smooth as expected, and the cryostat was put on a vacuum pump for a day to allow the ion pump to latch. There was one instance where the filter wheel controller required a restart because it was unable to receive commands. The restart occurred during afternoon checkout, and no time was lost.

Agile / SoonerCam: The Agile camera is non-operational due to a failed thermoelectric cooler. The camera and ICC are currently powered down. The camera is warm and no further repair work is scheduled because we plan to decommission the camera. The Agile instrument rotator is still not performing nominally, and we will be troubleshooting it further to prepare for SoonerCam. SoonerCam parts are on hand, and assembly and software development will begin after the first of the new year.

ARCES: As reminder to all ARCES users, we discovered that the FITS header keyword for DATE-OBS was incorrect by approximately 45 minutes, indicating a future time when an image was written. The problem began on or after August 27, 2024. If time stamps are important for your echelle observations, please take note.

DIS: System is powered down and warm. Decommissioning plans have begun.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The instrument is usable for laser ranging. The observing team hit 6 reflectors on two different observational nights — well done! The instrument had been experiencing some issues with its cooling water flow. Kinked water lines to the laser were identified and repaired.

We held a public Open House at APO on October 11, during which we welcomed roughly 200 visitors to APO for tours, talks and interactive exhibits. Thanks to the nearly 30 volunteers from APO, Sunspot Solar Observatory, and the NMSU Astronomy Department who helped to make this event a tremendous success.

There were three class visits in Oct-Nov and another one coming up at the end of this week. Currently most of the training responsibilities have been transferred over to Russet and Amanda.

The 3.5m telescope has been working fairy well. We still have occasional (seasonal) motion errors, but we haven't seen them increase so we haven't further tuned the axis drives. There was a motor amplifier fault with the tertiary mirror, which was corrected by homing the mirror. These events happen pretty infrequently but their root cause is difficult to track down.

On ARCSAT, the Dcam-spare camera was cleaned to remove water spots but without much success. We are likely going to replace it with the primary DIS slitviewer. Note added in proof: this swap was made – Dcam-spare was replaced with Dcam. UVa-cam is still available. We have not had much luck testing BYUCam so we may send it back to FingerLakes for repair/evaluation.

For KOSMOS, we repaired the cold strapping in a temporary sense, meaning the constrained wired cold straps were put back in place because we were unable to get braided copper straps to properly silver solder to the cold head. During engineering time last night we did some additional dark testing to verify that it's still holding up as a fix and it looks to be holding. There is some dew on the cryostat window due to a lack of purge air turned on when the instrument was put back together; the spots seem to be dried up now. During Q1 we will warm the instrument and pull the cryostat to clean the window. The spots should flat-field out in the mean time and are barely noticeable. The plan is to remake some of the parts for the cryostat separately so that the servicing time is minimized.

ARCTIC had some problems with the vacuum / cryostat ion pump and one instance where the filter wheel was unable to be commanded. We restarted the hardware controller in November.

Agile has not yet been taken apart but we have received all of the parts for SoonerCam and we will start assembling it and working on software development in January.

As a reminder, the ARCES FITS headers had a DATE-OBS keyword that was incorrect for some period of time starting on August 27, 2024. The reported value is about 45 minutes ahead of the true value. Users who require precise timing information should contact the observing staff for more details. Last week we had some intermittent ThAr lamp behavior where it was not being energized. Recent ARCES should look at their calibration files to confirm that they are not blank. We do not think it's a bulb problem; it is probably a cabling or power supply issue but we are still investigating this.

APOLLO had two sessions in last two months where we hit all 6 retroreflectors, which is a major accomplishment. We also tracked down some water line problems and repaired the damage.

Question from UC member: is the ARCES time offset value constant or does it depend on when data were taken? Bill thinks it's constant.

The Q4 schedule is posted. There is some OPEN time available on Dec 23A (short slot) and on New Year's Eve (note added in proof: the 12/31 time is now spoken for). Users interested in the Dec 23A time should send a request to Ben, Nancy, Russet, Amanda, and their institutional schedulers.

All requests are in and the Q1 schedule is in the works, we should have the schedule published around 12/10. The ARCSAT call should come out late next week. Note added in proof: the Q1 2026 schedule is now published and the ARCSAT call for proposals for Q1 was sent out on Dec 15; proposals are due by Dec 22.

The ARCSAT Q4 schedule is posted. There are two unscheduled weeks at the end of December.

• SoonerCam: Nearly all of the parts we are expecting have come in. We will begin working on this in January.
• KOSMOS grisms (no change from last month): we are still awaiting a decision on the proposal we submitted for funds to support the purchase of three new grisms for KOSMOS.
• ASPEN: Work on the design of the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review in spring 2026. We hosted a productive ASPEN team meeting at APO and NMSU in October. We submitted another NSF proposal in mid-November.
• Ocotillo: The TEG team is working on optics mounting. We have the disperser for the red channel in hand and mounts are being fabricated in the shop. We are working to characterize and provide software for the camera. Fiber assembly will begin in early 2026.

We are tentatively planning to launch the new website on January 13, 2026. We are currently working on updating the procedure for staff access for the portion of the website that will be behind a login. The old website will still be accessible, at least for some TBD time period, but the goal is for all users to migrate to the new site and let us know if there is critical information that they can no longer find.

Nancy presented a subset of slides from her presentations to the ARC Board of Governors meeting in early November to provide the UC reps with a summary of the 2025 operations, science achievements, and plans for next year.

We will have a joint APO-SDSS-SciServer booth at the January 2026 AAS meeting in Phoenix. We'd love to connect with faculty, staff, postdoc and student users of APO while at the meeting. Please stop by the booth, and please let us know if any of your department members are planning to present results derived from APO data so we can showcase them!

Nancy discussed the fact that we are exploring the possibility of working with an existing data archive to enable us to archive APO 3.5m data. In polling the UC reps, it seemed that there is broad support for this initiative. People agreed that this would enhance the scientific impact of APO over time, and no one seemed alarmed that the data would become public (after some proprietary period), particularly if there were a way for a user to opt-out. Nancy will provide more updates as they become available.

Open action items from previous meetings:

• Nancy/Sarah: follow up with Jim Davenport about the status of PyKOSMOS and report back. The update is that PyKOSMOS is openly available on GitHub and is being used by some groups. The tutorials have not yet been fully vetted but Sarah's class just used it and will be providing suggestions for improvements. The software is not locked down so if users wish to edit it in order to address a specific issue they are welcome to do so. Status: CLOSED.
• Joanne Hughes: put the KOSMOS MOS data reduction software on the wiki. Joanne is waiting for an update from her colleagues at the College of Idaho. Status: OPEN.
• UC reps: remind your users to review the Q4 schedule and request OPEN/DD01 time if they can make a good case for it. Status: OPEN.

New action items from this meeting:

• UC reps: alert your users that if they plan to attend the Jan. 2026 AAS meeting and present results derived from APO data they should notify Nancy.
• UC reps: please discuss the idea of archiving our 3.5m data with your users and report back with any reactions, either positive (e.g., advantages that they see to having a data archive) or negative (e.g., potential issues or concerns).

None.

There was no objection to maintaining the same meeting schedule in 2026, i.e. the first Tuesday of the month at 10:30 am MT. The only exception will be in January, since the first Tuesday conflicts with the AAS meeting so we moved it one week later. Therefore, the 2026 meeting dates will be on Jan 13, Feb 03, Mar 03, Apr 07, May 05, Jun 02, Jul 07, Aug 04, Sep 01, Oct 06, Nov 03, Dec 01. Nancy will send around an updated Zoom meeting invitation.

Attending: Nancy Chanover (NMSU), Aleksandr Mosenkov (BYU), Russet McMillan (APO), Anne Verbiscer (UVa), Adam Kowalski (CU), Misty Bentz (GSU), Ben Williams (UW), Moire Prescott (NMSU), Joanne Hughes (Seattle U), Chip Kobulnicky (UWy), Michael Hayden (OU), Eric Bellm (UW), Sarah Tuttle (UW), Bill Ketzeback (APO), Gordon MacDonald (APO)

• Colorado - Several CU users were wondering about the status of data reduction software for KOSMOS, and whether PyKOSMOS is considered finished and ready for widespread use or whether people should still be using standard IRAF routines. A user found that the spectra are tilted so much that they need to use the Marsh algorithm rather than the Horn algorithm in the reduction, and the PyKOSMOS documentation currently does not address this. Nancy and Sarah Tuttle took the action item to follow up with Jim Davenport on this and report back.
• BYU - nothing to report
• Oklahoma - nothing to report
• UVa - nothing to report
• Wyoming - nothing to report other than general interest in the timetable for the KOSMOS repair
• Georgia State - nothing to report
• NMSU - nothing to report
• Washington - nothing to report other than general interest in the timetable for the KOSMOS repair
• JHU - nothing to report (by email)
• Seattle - nothing to report regarding recent observations, but Joanne had a comment on the topic of KOSMOS data reduction. She and her collaborators had a College of Idaho student working with Jon Holtzman on software for slit mask/MOS data reduction. The software is pretty stable and is publicly available but it is not on the wiki yet. Joanne said she would be happy to share it and took the action item to put it on the wiki.
• NAPG - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 9/03/25 – 10/07/25

1) Overview

Monsoonal patterns continued for much of September, with unsettled weather affecting all but a small handful of nights this month. There were no visiting classes or PI instruments staying on site during the month. However, we did host daytime tours and had remote training sessions this past month. The 3.5m Night Operations team saw the departure of both Candace Gray and Mark Croom. We wish them both in their future adventures!

The site will be holding an open house event for the public (daytime only) on October 11. Science demonstrations, public talks, and tours of the telescopes will be the highlights of the four-hour event.

2) Operations

3.5m Telescope: Telescope is working as expected. Seasonal motion errors continue to occur infrequently. We anticipate that there will need to be some tuning of the axis drives by mid-November. This past Saturday, there was an occurrence where one of the three axial actuators for the secondary mirror did not move after an instrument/ port change. The operator corrected the problem by homing the secondary. The weather at the time was poor, so no time was lost.

0.5m Telescope: Telescope is working as expected. Dcam-spare and UVAcam are both available options for users.

KOSMOS: As discussed last month, the increase in dark current warranted opening the cryostat for inspection. Three of the four thermal connections from the liquid nitrogen can to the CCD cold block had failed, leaving only a single thin connection. Repairs were delayed by the shipping of material from Europe. We are currently searching for a vendor to assemble the parts, as we have not had success ourselves.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled.

Agile: The camera is non-operational; the thermoelectric cooler failed again. The camera is warm, and we do not plan further repair work with this camera. We are planning on decommissioning the camera. The agile instrument rotator is still not performing nominally, and we are troubleshooting it further to prepare for SoonerCam.

ARCES: While working on automating the interorder light reductions and archiving the data in a new database, we discovered that the FITS header KEYWORD for DATE-OBS was wrong by approximately 45 minutes in the future of when an image was written. Further data mining revealed this occurred during the summer/fall of 2024 when the ICC experienced power supply failure and hard drive troubles. It was not caught that the operating system service that syncs time to the site timeserver was not performing. The problem would have started on or after August 27, 2024. If time stamps are important for your echelle observations users should take note. A report from a user that the new ThAr bulb, replaced on July 22nd, had very weak lines or missing lines in the mid and blue orders prompted us to replace the bulb again on September 29. Wednesday, September 30th, observers then reported that the ThAr counts were around 3250 DN last year, but only 3100 DN counts tonight. This was the last new HCL we had on the shelf. It may be these two bulbs had lower pressure argon gas fill and therefore those are the lines missing. Comparison with line lists would need to be done to confirm. More bulbs are on order; however, Thorium-Argon lamps of the same type and manufacture as we were purchasing years ago are no longer available. We are buying up one European vendors back stock but we do not know if these will be of the same lamp strength as the old bulbs.

DIS: System is powered down and warm. Decommissioning plans have begun.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The instrument is usable for laser ranging.

APO will be hosting an Open House this coming weekend, during which we will be giving public demos, tours, and talks over a 4-hour event.

The 3.5m telescope is performing as expected for this time of year. We had a failure of one of the actuators on the secondary mirror, which froze when changing between two ports. Homing of the mirror corrected the problem with no further issues; this was caught during poor weather so no science time was lost.

The 0.5m telescope is working as expected; Dcam-spare and UVAcam are available to users for Q4.

KOSMOS is warm and taken apart as a result of increased dark current reported by the users. At last month's Users Committee meeting we concluded that it was becoming unusable for science and the consensus was that we should not wait until December to do an inspection. Upon taking it offline it was discovered that of the four thermal connections between the LN2 cold strapping and the cold block that cools the CCD, three of them were broken; only one was providing cooling. We subsequently ordered new strapping material to do the repair; the material was delayed because it came from Europe. Once it arrived it became apparent that the repair would be more difficult than what we were comfortable doing on site. We contacted several vendors and got quotes, and ultimately the cold head block and various pieces were sent out to a shop in Albuquerque. They need to procure some materials to do the repair, but we are hoping that by the week of Oct 13-17 the repairs will be completed. Then we will pick it up, return it to APO, and do the vacuum baking out to prepare the dewar for service. Ideally we are hoping that it could return to service late in the week of Oct 13-17 but it could be later, depending on how quickly the shop can procure their needed materials and complete the repair. We will continue to update the scheduled KOSMOS users as we learn more about the timetable.

ARCES: While working on streamlining the software for calculating IOL it was discovered that the DATE-OBS keyword in the FITS headers was wrong (45 min in the future from when the data file was written). After some data mining we found that this occurred in late August 2024 but it was not caught until now. If time stamps are important for your echelle observations ARCES observers should take note and we can provide the detailed time offset for anyone for whom this is critical. There was a report from a user a few weeks ago that the new ThAr bulb that was replaced in July 2025 had some weak/missing Ar lines in the blue orders. We replaced it with a different spare on September 29 and the next day we learned that the new bulb was slightly fainter than the bulb from a year ago so ARCES users should also note this. These hollow cathode lamps are no longer being made with Th metal filaments and it is increasingly hard to find spare lamps on the shelf. We just purchased a supply so that we have some spares and we hope that each one will last a few years. Given that it is becoming harder to find the old style ThAr lamps an alternative source may need to be identified.

ARCTIC, NICFPS, TripleSpec and APOLLO are all functioning nominally. DIS and Agile are still slated for decommissioning.

The Q4 schedule is posted. There is a fair amount of OPEN/DD01 time in late October (dark time, all B halves). We hope to use some of it to pay back KOSMOS users who had to give up their time but we're not committing to that until we know when KOSMOS will be returning. Some of the scheduled KOSMOS time may need to be allocated to other users, ideally from the same institution. There is additional OPEN/DD01 time later in quarter, including a limited number of A halves or partial A halves. A huge thank you to Russet for doing such a great job with the challenging schedule for this quarter.

The ARCSAT Q4 schedule is posted. It is pretty full, but there is some time available later in the quarter. The two available instruments are UVa-cam (larger FOV) and Dcam-spare (smaller FOV and less oversampled). Dcam-spare did have some frost on the window after shutdown; it is gone now but we can still see signatures of it on the detector. They flat-field out but the frames look ugly when taking data.

• SoonerCam: Parts have been trickling in. So far we received the fiber and software developer's kit but we're still waiting on the fiber to coaxpress converters. We will dig into this after early November.
• KOSMOS grisms (no change from last month): we are still awaiting a decision on the proposal we submitted for funds to support the purchase of three new grisms for KOSMOS.
• ASPEN: We recently learned that a proposal we submitted for funds to support the development of the new echelle spectrograph was not selected for funding. Work on the design of the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review in early spring 2026. We are hosting an ASPEN team meeting at APO and NMSU this week.
• Ocotillo: The vibration stabilization bench and optical table have been delivered, along with the enclosure. We are starting to get optical mounting parts and a student is working on the software and data side. Late this week the fibers should arrive, and the optics will be coming in next few weeks, including the grating. Sarah plans to submit an NSF ATI proposal for the robot side of the third channel.

There are a number of events taking place over the next several months:

• We have 4 class groups coming APO in Q4. A fifth one will be moved to Q1. Please be patient with the site staff, who will be shorthanded during this time!
• We are in the midst of an in-person ASPEN team meeting at NMSU/APO this week.
• We are holding a public-facing Open House at APO on Saturday October 11. This will include site and telescope tours, activities, and talks at the Sunspot Astronomy and Visitor's Center. We look forward to welcoming the public back to the site; our last Open House was in March 2020.
• The ARC Board of Governors meeting is on November 4. Please submit all science highlights to Nancy no later than Monday October 27.
• The January 2026 AAS meeting will be in Phoenix, and we plan to have a booth. There was no motivation for a special session so we did not submit a proposal.

Open action items from previous meetings:

• Nancy: follow up with UWy KOSMOS user to determine severity of dark current issue. Status: CLOSED.
• UC reps: remind your users to review the Q3 schedule and request OPEN time in September if they can make a good case for it. Status: CLOSED.
• UC reps: poll your users about a Jan. 2026 splinter session at the AAS for APO science highlights and networking (or other ideas!). Status: CLOSED.

New action items from this meeting:

• Nancy/Sarah: follow up with Jim Davenport about the status of PyKOSMOS and report back.
• Joanne Hughes: put the KOSMOS MOS data reduction software on the wiki.
• UC reps: remind your users to review the Q4 schedule and request OPEN/DD01 time if they can make a good case for it.
• UC reps: remind your users to provide Nancy with science highlights from 2025; she needs to receive them no later than Monday October 27.

We discussed the timeline of events that led to the temperature issues for KOSMOS. In January 2025 the chip temperature increased. Data taken in late winter and early spring were probably not affected, but users started to notice the issue in the mid/late spring.

Gordon is working on a new release for TUI (v3.2), which will be coming out soon. The new version cleaned out some old scripts and removed the option of selecting instruments that are being decommissioned. The most exciting aspect is that he is working on packaging to make the software installation process more simple for users, especially students. Although we encourage users to stay current with their TUI versions, older versions of the software will still work.

The next Users Committee meeting is currently scheduled for Tuesday November 4, 2025, which directly conflicts with the ARC Board of Governors meeting. Therefore the November UC meeting is canceled, and we will meet next on Tuesday December 2, 2025, at 10:30 MST.

Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Misty Bentz (GSU), Aleksandr Mosenkov (BYU), Anne Verbiscer (UVa), Michael Hayden (OU), Kevin Schlaufman (JHU), Joanne Hughes (Seattle U), Moire Prescott (NMSU), Chip Kobulnicky (UWy), Ben Williams (UW)

• Georgia State - nothing to report
• Wyoming - nothing to report
• NMSU - nothing to report
• Washington - nothing to report (by email)
• Oklahoma - nothing to report
• UVa - Anne asked about whether there are any backup systems in place to avoid another occurrence of the recent network issue. This was discussed in more detail below.
• JHU - nothing to report
• BYU - nothing to report
• Seattle - Joanne reported that the dark current on KOSMOS has noticeably increased from April to now. See KOSMOS discussion in the below site report for more details.
• Colorado - no report
• NAPG - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 8/06/25 – 09/02/25

1) Overview

The month of August experienced a mix of late afternoon monsoon storms that either delayed opening or affected many of the A half observing programs. We had two visiting instrument teams from U. Virginia this month. There was a failure of one of the main site network subnets that prevented observing and took down site phones as well as communications via TUI. Email was able to be received and sent from off site but not on site. We tracked the problem to a failure of a managed network switch and we were able to replace it with a spare. There was some difficulty loading the management given the switches were different models. The root cause is still not well understood as it looked like a cascading failure including the site DHCP server that also resulted in loss of communications with the site DNS servers. The problem took a little over 24 hours to resolve.

The hiring committees for the Telescope Engineer and Night Operation positions are in the process of reviewing candidates. There were a large number of applications for each opening.

2) Operations

3.5m Telescope: Telescope is working as expected. Seasonal motion errors have been infrequent. A full remap of the tertiary rotation was redone and this seems to have corrected the reported position errors from last month's report.

0.5m Telescope: Telescope is working as expected. ACP Library support errors are still occurring even with the dcam-spare camera swap but with much lower frequency. Dcam-spare had a loss of CCD chamber integrity and was forming ice on the detector while cold. The camera was serviced twice but now appears to have water spots on or near the detector surface. Cary Smith will attempt to clean but it is not without risk to the bonding wires of the detector. University of Virginia tested another surplus Apogee camera during their coordinated observing run with DSSI on the 3.5m. The off-axis guider has not been very reliable, requiring power cycles.

KOSMOS: System is cooled and stable. Increased dark current for long exposures has been confirmed. We attempted a vacuum servicing of the cryostat but without much luck. We anticipate having to open the vacuum vessel in the clean room sometime during Quarter 4 to investigate possible thermal shorts or opens. kcamera-ICC was backed up over shutdown.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. Troubleshooting is continuing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled.

Agile: The camera is non-operational, the thermoelectric cooler failed again. The camera is warm and we do not plan further repair work with this camera. We are planning on decommissioning the camera. The agile instrument rotator is still not performing nominally and we are troubleshooting it further to prepare for SoonerCam.

ARCES: The CCD reservoir for the cooling system was brought back to temperature. IOL levels are quite good but slowly worsening. We hope that it will stabilize and reverse direction with cooler ambient temperatures as we have seen in previous fall time frames. Work continues on a replacement and modern ICC, so far testing is going well. A commissioning report is being worked on.

DIS: System is cooled but in an unknown state for science. Decommissioning plans have begun.

NICFPS: System is cooled and usable. The ICS software has needed multiple restarts over the past month. The cause is unclear at this time.

TripleSpec: System is cooled and usable.

APOLLO: The instrument is usable for laser ranging.

There was a recent failure of the main site network's subnet switch, which took out the site phones and 1075 network. This switch handles the common communications network for all site communications, on-site computers, and non-telescope-specific instruments and computers. The switch was replaced and it took about 24 hours to get everything back up and running correctly. It was an old switch so we had no direct spare; it was replaced with another managed switch. These need to be managed switches because they handle communications that pass through some other specific configurations for wifi security and other security protocols. Because it was a managed switch it was not a simple plug-and-play quick swap; the major part of the recovery was to get the network back up and running. Although this was all accomplished by 4 pm the next day, it did unfortunately result in one night of down time. It would be cost prohibitive to reengineer the entire network so there are no plans to overhaul the site network configuration. We are trying to source a replacement for the switch that we used as a spare and will evaluate what other steps we can take to ensure that we are better prepared for this kind of situation if it arises in the future.

Regarding the open positions, the hiring process is moving forward. Also, we welcome Tim McQuaid, a third-year graduate student at NMSU, who will be replacing Mark Croom as the emergency fill-in observing specialist. Tim has already begun his training so you will likely encounter him soon.

We continue to have challenges with the camera(s) on the 0.5m. It is possible that the DIS camera can be used once the decommissioning is further along. University of Virginia brought a spare Apogee camera for use on ARCSAT; it is still not known whether that can be used by the broader ARCSAT user community.

The KOSMOS vacuum servicing didn't resolve the issue of high dark current so we will have to open up the cryostat to see if we can figure out what is causing a decreased hold time or increase in dark current. We are currently planning to do this during Q4; the science schedule indicates that it may not be possible until early December unless the issue becomes critical and we need to take the instrument out of service. Chip reported that a recent UWy user suggested that the dark current is currently so high that the instrument is unusable for faint targets without doubling or tripling the exposure time. Nancy will follow up directly with that user to ascertain if the problem has worsened. This would be an argument for servicing KOSMOS sooner, but we need to balance that with the numerous class visits that will be scheduled in the first two months of Q4, most of which have requested to use KOSMOS.

ARCES had been displaying increased inter-order light that would indicate some form of contamination in the light path of the CCD. We warmed up half of the cryostat while keeping the shield cold so that the water vapor would migrate to shield. That did improve things significantly but subsequently things degraded somewhat; we are now hoping that it will stabilize or reverse direction. The upgrade to a modern computer for the ARCES ICC is underway.

NICFPS and TripleSpec are operating as expected. DIS is powered down. APOLLO has been laser ranging and we were recently able to get all 5 retroreflectors but it is still not at peak performance.

There is some OPEN time remaining in September (last month of Q3). We have received requests for some of it, but not all. To request this time please follow the standard procedure by emailing your request to Ben Williams, Russet McMillan, Amanda Townsend, Nancy Chanover, and your institutional scheduler. Be sure to include the specific slot you are requesting (or specify that any time slot will do) and a short justification.

The Q4 schedule is in the works; we expect to have a first draft in about a week.

September 8-17 (next week!) is the only open time remaining in the ARCSAT Q3 schedule.

• SoonerCam: we are ordering parts!
• KOSMOS grisms (no change from last month): we are still awaiting a decision on the proposal we submitted for funds to support the purchase of three new grisms for KOSMOS.
• ASPEN (no change from last month): we are still awaiting a decision on the proposal we submitted for funds to support the development of the new echelle spectrograph. Work on the design of the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review in early 2026.
• Ocotillo (no change from last month): a number of purchase orders were executed and we expect the first batch of hardware to come in within the next month or so.

We are close to having something operational. All of the requested pieces and updates were implemented. Although it is not yet finalized, users are encouraged to start using it: https://mainapo.apo.nmsu.edu UC reps: please notify your users that they should start using the new website and report any bugs to you, to be forwarded on to Ben Williams.

There are a number of events taking place over the next several months:

• We have 4 class groups coming APO in Q4. A fifth one will be moved to Q1. Please be patient with the site staff, who will be shorthanded during this time!
• There will be an in-person ASPEN team meeting at NMSU/APO in early October.
• We are holding a public-facing Open House at APO on Saturday October 11. This will include site and telescope tours, activities, and talks at the Sunspot Astronomy and Visitor's Center. We look forward to welcoming the public back to the site; our last Open House was in March 2020.
• The ARC Board of Governors meeting is on November 4; we will request science highlights from everyone at next month's meeting, with a due date in late October.
• The January 2026 AAS meeting will be in Phoenix, and we plan to have a booth. October 6 is the abstract deadline. The deadline for Splinter Session proposals is September 25; does anyone have an interest in an APO science-fest sort of session? UC reps: please poll your users and email Nancy with opinions.

Open action items from previous meetings:

• UC reps: ask your users to complete the survey from FAWG (per Nancy’s email sent on 7/23/25). Status: CLOSED.

New action items from this meeting:

• Nancy: follow up with UWy KOSMOS user to determine severity of dark current issue.
• UC reps: remind your users to review the Q3 schedule and request OPEN time in September if they can make a good case for it.
• UC reps: poll your users about a Jan. 2026 splinter session at the AAS for APO science highlights and networking (or other ideas!).

None.

The next meeting will be on October 7, 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Sarah Tuttle (UW), Chip Kobulnicky (UWy), Ben Williams (UW), Michael Hayden (OU), Misty Bentz (GSU), Eric Bellm (UW), Moire Prescott (NMSU)

• Wyoming - nothing to report
• Washington - nothing to report
• UVa - nothing to report (by email)
• Seattle - nothing to report (by email)
• Oklahoma - nothing to report
• NMSU - There is still an interest in trying to understand/mitigate the abnormally high background seen when taking long (20-30 min) exposures with KOSMOS. It manifests as a snow pattern in the background pixels. The engineering staff is still working to address this issue but if other users have seen this in their data it would be really helpful to know.
• NAPG - no report
• JHU - nothing to report (by email)
• Georgia State - nothing to report
• Colorado - nothing to report (by email)
• BYU - nothing to report (by email)

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 7/02/25 – 08/05/25

1) Overview

Summer shutdown activities occupied the first half of the month. Surprisingly in the second half of July we were able to get several nights of on-sky science despite the monsoon weather.

Reminder: We have position openings for 3.5m Chief Telescope Technologist (Engineer) and Mechanical Engineer, Lead. These positions close on August 15 so please spread the word.

Mechanical Engineer: https://careers.nmsu.edu/jobs/mechanical-engineer-ld-remote-locations-new-mexico-united-states

Chief Telescope Technologist: https://careers.nmsu.edu/jobs/chief-telescope-technologist-remote-locations-new-mexico-united-states

We will be hiring only one person but have two postings to reflect different academic degrees and experience levels; interested candidates should apply for the one that best matches their skill set and preparation.

2) Operations

3.5m Telescope: Telescope is working as expected. Seasonal motion errors have been more frequent. The tertiary rotation mechanism has experienced some issues after a software remapping of port positions. Further position refinements may be required.

0.5m Telescope: Telescope is working as expected. Users have experienced several camera problems with both FlareCam and dcamera-spare related to frosting/icing or inability to cool properly. Cary serviced dcamera-spare by replacing both cooling fans and recharging the CCD vessel with gas. The off-axis guider has not been very reliable, requiring power cycles.

KOSMOS: System is cooled and stable. Increased dark current for long exposures has been confirmed. We attempted a vacuum servicing of the cryostat but without much luck. We anticipate having to open the vacuum vessel in the clean room sometime during Quarter 4 2025 to investigate possible thermal shorts or opens. kcamera-ICC was backed up over shutdown.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. Troubleshooting is continuing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled. We replaced the ion pump cable and moved the controller back to the intermediate level.

Agile: The camera is non-operational; the thermoelectric cooler failed again. The camera is warm and we do not plan further repair work with this camera. We are planning on decommissioning the camera. The Agile instrument rotator is still not performing nominally and we are troubleshooting it further to prepare for SoonerCam.

ARCES: The CCD reservoir for the cooling system is currently warm and not usable for science. We are keeping the shield reservoir cold. During shutdown we did a vacuum servicing but shortly after cooling the inter-order light showed elevated contamination. We have taken it out of service to address this problem. Work continues on a replacement and modern ICC, and so far testing is going well. A commissioning report for the new ICC is being worked on.

DIS: System is warm and out of service. Decommissioning has begun.

NICFPS: System is cooled and usable. The ICC was backed up fully during shutdown.

TripleSpec: System is cooled and usable. The ICCs (tspec and tcamera) were backed up during shutdown. Tcamera-ICC experienced another failure of one of its RAID hard drives and it needed to be rebuilt.

APOLLO: A team from NASA returned to site this past month to address issues with optical alignment and laser power issues. The instrument is again available for laser ranging but additional work will need to be done upgrading the power measurement equipment and working on some of the thermal metrology.

All-Sky camera: 3.5m engineering staff has been working with the ALCOR manufacturer to remedy camera and software problems. Troubleshooting continues.

The summer shutdown is complete; it was fairly short this year. We accomplished daytime engineering in the first week and used the second week for on-sky engineering. All of the necessary baseline tasks in order to return the telescope to scientific operations were completed. This includes handwashing all the mirrors, a spring cleaning of the enclosure and instrumentation, greasing/lubricating various moving parts, and vacuum servicing KOSMOS and ARCES.

The KOSMOS servicing did not seem to alleviate the high dark current reported last month, so we may need to unseal the cryostats and go into the instrument to investigate it further. We currently plan to do this during Q4. The ARCES servicing went as expected; it was OK for a short time after cooling but then the inter-order light ratios plummeted (indicating lots of scattered light), which means the contamination migrated within the instrument. It will be taken back out of service to mitigate that over the next 1.5 weeks; we've already started that process, and the instrument should be available for use the night of August 22 (note added in proof: it was back on August 15!).

The 3.5m telescope is working as expected; the seasonal motion errors are more frequent but not unexpected given the current season.

The 0.5m telescope is working as expected but the cameras (FlareCam and dcam-spare) continue to have problems. There was a loss of vacuum in the CCD canisters, which resulted in frosting/icing within the dewar. Cary serviced dcam-spare and got it back to reliable performance but FlareCam is less reliable and continues to get worse with age.

APOLLO had numerous laser and optical alignment issues over the last month and a NASA team came back to the site to work on it. We believe the instrument is now functional but there may be additional work to be done to address a recently discovered laser frequency issue.

As a reminder, we have a current opening (covered by two different job postings) for the 3.5m chief telescope engineer. We are currently reviewing applications for telescope operator/support astronomer position.

The 3.5m schedule for Q3 has been in flux given the recent echelle engineering. Users who lost observing time due to the echelle servicing or weather are especially encouraged to request OPEN/DD time in Q3. To request this time please follow the standard procedure by emailing your request to Ben Williams, Russet McMillan, Amanda Townsend, Nancy Chanover, and your institutional scheduler.

All allocations for Q4 have been sent to the institutional schedulers; proposals are due on August 25. Note that the allocation emails stated that our ability to offer a virtual training in Q4 is uncertain due to staffing limitations; we indicated that we MAY offer it in Q4.

Next week is the only open week remaining in the ARCSAT Q3 schedule.

• SoonerCam: we received a modest number of survey responses and will proceed using the information we have. The camera was purchased and a meeting is scheduled in two weeks to discuss the next steps.
• KOSMOS grisms: we are still awaiting a decision on the proposal we submitted for funds to support the purchase of three new grisms for KOSMOS.
• ASPEN: we are still awaiting a decision on the proposal we submitted for funds to support the development of the new echelle spectrograph. Work on the design of the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review in early 2026.
• Ocotillo: a number of purchase orders were executed and we expect the first batch of hardware to come in within the next month or so.

Please see the site report above.

Open action items from previous meetings:

• UC reps: ask your users to complete the survey regarding needs/desires for a high speed imaging capability. The link to this survey was sent out to 35m-general on May 6, 2025 by Mukremin Kilic. STATUS: CLOSED.
• UC reps: ask your users to send Nancy the bibliographic information for any papers published in 2024-2025 that are resulting from 3.5m or ARCSAT data. STATUS: CLOSED
• UC reps: ask your users to complete the survey from FAWG (per Nancy’s email sent on 7/23/25). Status: OPEN.

New action items from this meeting:

• None.

None.

The next meeting will be on September 2, 2025 at 10:30 MDT.

• BYU - nothing to report
• Colorado - no report
• Georgia State - nothing to report
• JHU - nothing to report
• NAPG - no report
• NMSU - nothing to report
• Oklahoma - nothing to report
• Seattle - nothing to report
• UVa - nothing to report
• Washington - nothing to report
• Wyoming - nothing to report in terms of 3.5m telescope usage, but informationally: Wyoming will be advertising a tenure-track astronomer position in the coming days. It will have an August 15 deadline for a January 2026 start date.

The detailed site report is included below.

3.5-m Telescope and Instruments Highlights, 6/03/25 – 07/01/25

1) Overview

The first half of June was rather dry. A large lightning strike caused a fire in difficult terrain, north of Cloudcroft on Mescalero tribal land, which reached over 800 acres. At the time of this report it is currently 97% contained. The last two weeks of June have seen a welcome relief in the dry conditions with the start of summer monsoonal weather patterns. The month of June had one visiting PI instrument scheduled but the team cancelled their travel and supported staff remotely. An REU group from U. Wyoming were additional visitors this month. Two large public outreach groups of high school and college summer science programs visited and were given tours. We had an inadvertent power cycle on two important UPS systems that power cycled several telescope subsystems including a few instruments. We were able to quickly recover.

As a reminder, summer shutdown is scheduled for July 7 - 17. Relatively short with only standard instrument and telescope maintenance.

2) Operations

3.5m Telescope: The telescope is working as expected. Seasonal motion errors have been infrequent. The secondary mirror was homed and the telescope positions reinitialized as part of the UPS power recovery mentioned above. A refinement in pointing was needed over the weekend as well.

0.5m Telescope: The telescope is working as expected. ACP Library support errors are still occurring even with the dcam-spare camera swap but with much lower frequency. The off-axis guider has not been very reliable, requiring power cycles.

KOSMOS: System is cooled and stable. A report of increased dark current for long exposures was received by a user. We hope to address this over summer shutdown by doing a vacuum servicing of the instrument.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. Troubleshooting is continuing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled. The CCD had an instance of a dropped quadrant as a result of the UPS power cycle.

Agile: The camera is non-operational; the thermoelectric cooler failed again. The camera is warm and we do not plan further repair work with this camera. We are planning to decommission the camera. The Agile instrument rotator is still not performing nominally and we are troubleshooting it further to prepare for SoonerCam.

ARCES: System is currently up and usable. The instrument seems to be consuming LN2 at a greater rate. We will likely try to address this over summer shutdown. Work continues on a replacement and modern ICC.

DIS: System is cooled but in an unknown state for science. Decommissioning plans have begun.

NICFPS: System is cooled and usable. The ICS software has needed multiple restarts over the past month. It is unclear at this time the cause.

TripleSpec: System is cooled and usable.

APOLLO: The system is continues experiencing some technical issues with the laser and thermal control at the time of this report. A team from NASA is on site this week to address the issues. Until repaired the instrument is not usable for laser ranging.

There are several open B-halves available in late July and early August, including dark time! Users should look at the schedule and follow the usual channels for requesting this time (i.e. email Russet, Amanda, Ben, Nancy and their institutional scheduler when submitting requests, and provide a proposal cover page if you don't already have a program scheduled for the current quarter).

There are two weeks open on the Q3 ARCSAT schedule in early August and early September. Users should look at the schedule and follow the usual channels for requesting this time (i.e. email Russet, Amanda, Ben, Nancy and their institutional scheduler when submitting requests, and provide a proposal cover page if you don't already have a program scheduled for the current quarter).

The Ocotillo purchase orders are largely in or are in the process of being generated and submitted. Procurement times are uncertain. The SoonerCam survey results will be collated soon.

Please send Nancy any references for 3.5m-related publications (anything published from Jan 1 2024 to now). The nominal deadline was June 30 but we have received relatively few responses so users are encouraged to complete this action item. See last month’s minutes for explanation of why these metrics are important. The listing should include refereed publications and student theses and dissertations (not conference abstracts unless they are peer reviewed) that made use of data acquired with the 3.5m and/or ARCSAT, published from 2024 to the present. If a paper has been submitted to a journal but has not yet completely gone through the review process, please include that as well, with the name of the journal and “submitted.”

We have two vacancies on the 3.5m side that we are eager to fill!

1) Observing specialist - there are two postings for this; applicants should choose the one that best matches their education and experience level:

• Support Astronomer: https://careers.nmsu.edu/jobs/support-astronomer-nmsu-satellite-location-new-mexico-united-states
• Telescope Ops Specialist: https://careers.nmsu.edu/jobs/telescope-ops-spec-remote-locations-new-mexico-united-states

2) 3.5m Telescope Engineer - there will be two postings for this; applicants should choose the one that best matches their education and experience level:

• Chief Telescope Technologist: https://careers.nmsu.edu/jobs/chief-telescope-technologist-las-cruces-new-mexico-united-states
• Mechanical Engineer: posting is coming soon - check back at https://careers.nmsu.edu !

These will be advertised in the July AAS Job Register but please share this announcement with anyone whom you think would be well qualified for these positions.

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: CLOSED. Nancy submitted the proposal on 6/23/25.
• UC reps: ask your users to complete the survey regarding needs/desires for a high speed imaging capability. The link to this survey was sent out to 35m-general on May 6, 2025 by Mukremin Kilic and it is also here: https://docs.google.com/forms/d/e/1FAIpQLSeJG6zQg7YtGxGhAtaKULHyzZVZe29uHCiegcHdM0edglN1gw/viewform Bill is planning to collate the results, but if there are too few responses now, the survey will stay open longer. STATUS: OPEN.
• UC reps: ask your users to send Nancy the bibliographic information for any papers published in 2024-2025 that are resulting from 3.5m or ARCSAT data. STATUS: OPEN

New action items from this meeting:

• UC reps: remind your users to review the Q3 schedule and request OPEN/DD time if they can make a good case for it. STATUS: OPEN.

None.

The next meeting will be on August 5, 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Anne Verbiscer (UVa), Eric Bellm (UW), Aleksandr Mosenkov (BYU), Kevin Schlaufman (JHU), Joanne Hughes (Seattle U), Moire Prescott (NMSU), Adam Kowalski (CU), Chip Kobulnicky (UWy), Ben Williams (UW), Sarah Tuttle (UW)

• NAPG - no report
• Seattle - nothing to report
• BYU - nothing to report
• Wyoming - no report
• Oklahoma - no report
• Georgia State - nothing to report (by email)
• UVa - nothing to report
• Colorado - nothing to report
• JHU - nothing to report
• NMSU - There was a report from a user regarding the dark correction on KOSMOS data taken pretty recently. The dark level seems to be higher than it was historically, resulting in pixels that don't get corrected properly. The user contacted Russet about this. Nancy said that this will be discussed on our weekly operations call this Thursday and we will report back to Moire and the NMSU user if this issue and/or a mitigation strategy is understood. That said, if any other users have seen this issue – particularly for long exposures – please let Nancy know! Joanne mentioned that she took 3 x 900 sec darks with KOSMOS last Sunday night and also saw a high level of cosmic rays; she is willing to share the data if anyone wants to use them for comparison.
• Washington - nothing to report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 5/02/25 – 06/02/25

1) Overview

May was another month filled with unsettled weather but there were a few excellent nights near the end of the month with good seeing. The nights lost due to weather were mostly a result of cloud cover, high winds, elevated dust and humidity; we had very little precipitation this month. The New Mexico Governor has declared a state of emergency for the entire state due to severe drought conditions and extreme fire risk. A wildfire about 80 miles NNE of the observatory, which grew to larger than 750 acres, had the potential to threaten the observatory with smoke or ash had the winds had been from that direction, but nothing was reported. At the time of this report this fire as well as two smaller fires in the same area are declared 100% contained. There were no visiting classes or instrument teams to the observatory during the month of May.

As a reminder, summer shutdown is scheduled to start on July 7.

2) Operations

3.5m Telescope: Telescope is working as expected. Seasonal motion errors have been infrequent.

0.5m Telescope: Telescope is working as expected. ACP Library support errors are still occurring even with the dcam-spare camera swap but with much lower frequency.

KOSMOS: System is cooled and stable.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. Troubleshooting is continuing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled. The CCD was experiencing a strange bias issue that appears to have gone away when we partially warmed the instrument for an ion pump change. We are continuing to monitor.

Agile: The camera is non-operational; the thermoelectric cooler failed again. The camera is warm and we do not plan further repair work with this camera. The Agile instrument rotator is still not performing nominally and we are troubleshooting it further to prepare for SoonerCam.

ARCES: System is currently up and usable. Work continues on a replacement and modern ICC.

DIS: System is cooled but in an unknown state for science.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The system is currently experiencing some technical issues with the laser and thermal control at the time of this report. A portion of the system has been powered down while we wait for replacement parts. It may still be possible to energize just prior to a schedule run and still range.

The site has been incredibly dry but we got some much-needed rain last weekend even though we are not yet in the classical monsoon season. We will be keeping an eye out for seasonal telescope motion errors that may increase as the temperature warms; if that happens we may need to adjust the PID settings.

ARCSAT had some issues last night with the camera communicating with the software but it got ironed out.

We will investigate the KOSMOS issue reported above.

ARCTIC recently dropped a quad, which was recovered. There were also recent issues with the ion pump control; the cause was narrowed down to a bad cable. Once this is repaired we hope these issues will be reduced and we will not have to warm the instrument as much as we have recently.

Agile experienced a failure of the newly replaced TEC, and there are no current plans to repair the instrument further. We are moving ahead with SoonerCam (we now have the new camera in hand)! Auxiliary equipment for SoonerCam has not been ordered yet but that project is ramping up.

We are working on replacements for more modern computer/interface cards for ARCES to get us through the next few years.

There is no new status update for DIS.

NICFPS and TripleSpec are performing fine.

We are currently undergoing some technical issues with the laser on APOLLO that we're working through.

If we do any instrument servicing this summer it will probably take place outside of the summer shutdown window. Most likely it would only be KOSMOS, since ARCES, NICFPS, and TripleSpec don't need vacuum servicing, and KOSMOS generally only requires a 2-3 day turnaround. This could be accomplished during a period when the instrument is not scheduled for science.

The time in Q2 is fully allocated; no OPEN or DD slots remain. There are a couple of ToO paybacks slots that have not been called in yet.

The Q2 ARCSAT schedule has one week of OPEN time remaining (June 12-19). The long-standing policy for filter requests and changes is now published on the ARCSAT webpage in an effort to make it more visible. Users who are asking for filter changes must make the request at least 72 hours prior to the scheduled observing night when the new filters are needed. The APO staff cannot support filter changes on weekends and holidays.

The 3.5m summer shutdown is scheduled for 7-17 July, inclusive. We have received all requests for Q3 (thanks to everyone for getting them in on time or close to it!). So far we are not aware of any major conflicts. The schedule is currently being built and we hope to have a version to distribute next week. Once the Q3 schedule for the 3.5m is published we will issue a call for ARCSAT Q3 requests. ARCSAT will have the same shutdown schedule as the 3.5m so there will be less time available in Q3.

A replacement high speed imager, SoonerCam, is under development. A survey of all past/present/future users of such an instrument (i.e. current and former Agile users, or those who want to use a modern high speed imager) was distributed. We really need to hear from users concerning anticipated needs for frame rate, binning, etc. as this information will drive some design decisions. We plan to add a focal reducer but the pixels are currently very small. Here is the email sent to 35m-general requesting survey responses:

Dear APO 3.5m users, We are purchasing a new qCMOS high-speed camera, SoonerCam, to replace the old camera on Agile. This camera provides a read-noise of 0.3 e- in the ultra-quiet scan mode. It's a 4096×2304 pixel camera with 4.5 micron pixels. It can provide up to 25 frames/s in this mode. Using Agile's current setup, the camera provides 0.05 arcsec per pixel (or a field of view of 115“ x 205”).

Before finalizing the design and installation at the telescope, we would love to hear your thoughts or feedback on what would make this new camera suitable for your science needs.

If you are interested in using this new capability, can you please provide feedback on: https://docs.google.com/forms/d/e/1FAIpQLSeJG6zQg7YtGxGhAtaKULHyzZVZe29uHCiegcHdM0edglN1gw/viewform?usp=sharing

Thank you, On behalf of the SoonerCam team (including the Astro group at OU, Sarah Tuttle, Bill Ketzeback and the APO engineering/software team, and Nancy Chanover), -Muk

We really need users to complete this survey by the end of June. If anyone has specific requests or suggestions regarding desired capabilities for SoonerCam, that should be noted in the final question of the survey.

Work on the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review this calendar year. Another grant proposal is in the works.

Regarding Ocotillo, we are trying to get final quotes so that we can start purchasing materials and optics to assemble the first channel. Some vendors are slow in responsiveness these days.

This group is still meeting and exploring various options for the future of ARCSAT.

Please send Nancy any references for 3.5m-related publications (anything published from Jan 1 2024 to now). The deadline is June 30. Understanding the scientific usage and impact of the telescope is critical for evaluating future projects, initiatives, instrument concepts, etc., thus we need your help in updating our publication record! We are now participating in a cross-observatory analysis of scientific impact of ground-based telescopes, so it is especially important that we capture all publications resulting from APO observations. Any publications resulting from ARCSAT data are also requested. The listing should include refereed publications and student theses and dissertations (not conference abstracts unless they are peer reviewed) that made use of data acquired with the 3.5m and/or ARCSAT, published from 2024 to the present. If a paper has been submitted to a journal but has not yet completely gone through the review process, please include that as well, with the name of the journal and “submitted.”

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: OPEN. Nancy and Sarah are awaiting updated quotes from the grism vendor and then the proposal will be submitted.
• UC reps: ask your users to complete the survey regarding needs/desires for a high speed imaging capability. The link to this survey was sent out to 35m-general on May 6, 2025 by Mukremin Kilic, and is also included above. STATUS: OPEN.

New action items from this meeting:

• UC reps: ask your users to send Nancy the bibliographic information for any papers published in 2024-2025 that are resulting from 3.5m or ARCSAT data.

None.

The next meeting will be on July 1, 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Kevin Schlaufman (JHU), Misty Bentz (GSU), Russet McMillan (APO), Joanne Hughes (Seattle U), Zach Berta-Thompson (CU), Anne Verbiscer (UVa), Ben Williams (UW), Moire Prescott (NMSU), Sarah Tuttle (UW)

• JHU - nothing to report
• UVa - nothing to report
• Georgia State - nothing to report
• Oklahoma - no report
• NMSU - nothing to report
• Colorado - nothing to report
• BYU - nothing to report (by email)
• Washington - nothing to report (by email)
• Seattle - nothing to report
• Wyoming - no report
• NAPG - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 4/01/25 – 05/01/25

1) Overview

The frequency of higher winds and elevated dust levels improved somewhat during the month of April. APO experienced several days of particularly bad dust events ending in accumulation of several inches of snow. The precipitation melted within a day and did little to affect our high fire danger. We had a visiting class from OU and another observing team from NMSU on site this month. A NASA team was on site for APOLLO maintenance as well working with site staff.

2) Operations

3.5m Telescope: Telescope is working as expected.

0.5m Telescope: Telescope is working as expected. ACP Library support errors are still occurring even with the dcam-spare camera swap but with much lower frequency.

KOSMOS: System is cooled and stable.

ARCTIC: The diffuser rotation mechanism is still unreliable even after a full servicing. Troubleshooting is continuing. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime. The rest of the instrument is cooled and stable.

Agile: The camera is operational but only in slow readout mode. The Agile instrument rotator is still not performing nominally and we are troubleshooting it further.

ARCES: System is currently up and usable.

DIS: System is cooled but in an unknown state for science.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The system is currently experiencing some technical issues with the laser at the time of this report. The servicing trip had to be extended to attempt repairs. Hopefully an update will be able to be given at the time of the meeting.

The ARCTIC diffuser rotation mechanism has been challenging to repair. The symptom is that when commanded to rotate, the diffuser shifts in position and then stops. This is worse than having no rotation, so the rotation functionality is currently disabled. It will require a complete rebuild in order to get it working so this is on the longer-term to-do list.

The Agile instrument rotator is exhibiting problems. Unfortunately they are occurring too frequently for science, but too intermittently for detailed testing, which makes it hard to diagnose. This is still being worked on.

The time in Q2 is fully allocated; no OPEN or DD slots remain.

The Q2 ARCSAT schedule has one week of OPEN time remaining (June 12-19).

The 3.5m summer shutdown is scheduled for 7-17 July, inclusive. Institutional allocations for Q3 were sent out last week and all requests are due on May 23. DIS will no longer be made available for proposers.

A replacement high speed imager, SoonerCam, is under development. We expect to be able to share an information/specification sheet or white paper about the instrument fairly soon. In the meantime, a survey of all past/present/future users of such an instrument (i.e. current and former Agile users, or those who want to use a modern high speed imager) was distributed. We really need to hear from users concerning anticipated needs for frame rate, binning, etc. as this information will drive some design decisions. We plan to add a focal reducer but the pixels are currently very small. Here is the email sent to 35m-general requesting survey responses:

Dear APO 3.5m users, We are purchasing a new qCMOS high-speed camera, SoonerCam, to replace the old camera on Agile. This camera provides a read-noise of 0.3 e- in the ultra-quiet scan mode. It's a 4096×2304 pixel camera with 4.5 micron pixels. It can provide up to 25 frames/s in this mode. Using Agile's current setup, the camera provides 0.05 arcsec per pixel (or a field of view of 115“ x 205”).

Before finalizing the design and installation at the telescope, we would love to hear your thoughts or feedback on what would make this new camera suitable for your science needs.

If you are interested in using this new capability, can you please provide feedback on: https://docs.google.com/forms/d/e/1FAIpQLSeJG6zQg7YtGxGhAtaKULHyzZVZe29uHCiegcHdM0edglN1gw/viewform?usp=sharing

Thank you, On behalf of the SoonerCam team (including the Astro group at OU, Sarah Tuttle, Bill Ketzeback and the APO engineering/software team, and Nancy Chanover), -Muk

Work on the new optical echelle spectrograph continues with the goal of completing the Preliminary Design Review this calendar year. Another grant proposal is in the works.

We have no updates concerning Ocotillo.

This group is still meeting and exploring various options for the future of ARCSAT.

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: OPEN. The proposal is done; Nancy needs to confirm with NMSU's Office of Grants and Contracts whether they need to be involved in the submission since it's a small proposal. She plans to submit it before the next Users Committee meeting.
• UC reps: remind your users to review the Q2 schedule and request OPEN/DD time if they can make a good case for it. STATUS: CLOSED.

New action items from this meeting:

• UC reps: ask your users to complete the survey regarding needs/desires for a high speed imaging capability. The link to this survey was sent out to 35m-general on May 6, 2025 by Mukremin Kilic, and is also included above. STATUS: OPEN.

Nancy requested input from the UC reps concerning user needs/desires for data archiving. There was no clear consensus about what (if anything) APO should provide or facilitate in this area, but several UC members stated that it would be more useful to have reduced data available in an archive more so than raw data files.

The next meeting will be on June 3, 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Ben Williams (UW), Aleksandr Mosenkov (BYU), Michael Hayden (OU), Eric Bellm (UW), Ben Williams (UW), Anne Verbiscer (UVa), Moire Prescott (NMSU)

• Washington - nothing to report
• BYU - nothing to report
• UVa - nothing to report
• Colorado - nothing to report (by email)
• Seattle - Joanne observed last night so sent an email report: Amanda was very helpful with aligning the slit masks for MOS observations with KOSMOS; Joanne has also gotten better at making them.
• Georgia State - no report
• Oklahoma - nothing to report
• JHU - nothing to report (by email)
• NMSU - nothing to report
• NAPG - no report
• Wyoming - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 3/04/25 – 03/31/25

1) Overview

March was a bit unsettled weather wise with higher spring winds and elevated dust levels for a good portion of the month. Light snow flurries, with little accumulation, on two nights was the majority of the moisture we received in March. The second half of the student group from CU and one instrument team visited APO this month. A small number of high school and college spring break tours of the site and telescope were also given mid-March.

2) Operations

3.5m Telescope: Telescope is working as expected.

0.5m Telescope: Telescope is working as expected. ACP Library support errors are still occurring even with the dcam-spare camera swap. USB communications dropouts are now the most likely cause of the error. Discussions on how to proceed from here will be on going.

KOSMOS: There was some troubleshooting required following an inadvertent power down of part of the instrument. Documentation and the addition of extra labeling hopefully will correct this from happening in the future.

ARCTIC: Maintenance on the diffuser mechanism was performed however we believe there was a failure of part of the electronics that controls rotation. Troubleshooting is continuing. Diffuser rotation has been disabled while we attempt to repair. The mechanism that moves the diffuser in and out of the optical path is still functional in the meantime.

Agile: The camera was returned to the repair facility for additional troubleshooting. They transplanted our detector to a spare set of electronics boards, vacuum pumped and tested. We have it back now and are reinstalling at the writing of this report. I will give a further update during the meeting.

ARCES: System is currently up and usable. There was a recent report that flat fields are shifting. The effect is mentioned in the user manual however may be of larger magnitude than has been seen in the past. The orders appear to shift a few rows from image to image. The cause is unknown at this time especially since the instrument had been so stable for years. It is advised not to use super flats in your reductions unless you carefully compare individual raw images you are combining. No further update on this problem from last month.

DIS: System is cooled and usable.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The system is operational. The team was able to successfully receive returns off of the Next Generation Lunar Retroreflector (NGLR-1) on the Firefly Aerospace Blue Ghost Lander. This is a major accomplishment for the team and lunar ranging operations at APO.

The site has seen an increase in number of tour requests from various groups (school groups, amateur astronomer organizations, etc.). We've been working with an NMSU graduate student to help lead those tours, which has been an immense help. We want to be able to welcome the public to the observatory and adding this additional tour-giving capacity enables us to keep doing that.

The 3.5m telescope is functioning normally. The ARCSAT library support problems persist, even with the spare dcam in use (a new, basically out of the box camera). This could be due to the challenge associated with USB communication over such a long distance. We are currently unsure how to move forward because although there are some options, they are pricey. See below for further discussion of ARCSAT.

The ARCTIC diffuser rotator is still not working reliably. The staff continues to troubleshoot this, and in the meantime has disabled the rotation capability. The diffuser can still be used in the non-rotating mode. We are hoping to resolve this soon.

ARCES is still experiencing shifts in flat fields. We are unsure of the cause of it at this time, so we advise users not to use super-flats in their reductions until we can further understand the problem. We are hopeful that some of the ongoing PypeIt work for ARCES may provide some diagnostic information that can help us address this.

Agile is back from the repair shop but currently has two problems. (1) Something has happened with the software control of the camera readout rate. We can verify that the camera health is as expected but the current ICC is unable to change the readout speed from slow to fast, which means that the minimum exposure times are much longer than some programs would like. (2) The instrument rotator motor is not receiving power from the control cabinet. We verified that the amplifier is not putting out any current even though it does power up. We have a few spares, so are now looking into how those are programmed to see if a spare could be reprogrammed.

There was a KOSMOS problem reported earlier this month but it turned out to be a user error.

The APOLLO team is pleased to report that we got returns from the Next Generation Lunar Retroreflectors that were placed on the lunar surface by Firefly Aerospace's Blue Ghost 1 mission. Congratulations to all on this tremendous achievement!

The Q2 3.5m schedule is out; it started today. There is no DD time this quarter, and very little OPEN time due to the scheduling inefficiencies associated with several programs that required short time slots. There are a few bright B half slots in April starting on April 17, along with a few ToO payback slots towards end of quarter that will be rescheduled if the ToOs don't get called in. Users are encouraged to review the schedule and request any OPEN time that they can use.

The Q2 ARCSAT schedule just came out last week and it is relatively full.

Early discussions regarding the development of a replacement high speed imager, SoonerCam, are ongoing. We expect to be able to share an information/specification sheet or white paper about the instrument fairly soon.

Our preliminary proposal to the NSF for a replacement echelle was not invited for a full proposal. Work on the instrument continues with the goal of completing the Preliminary Design Review this calendar year, and additional sources of funds are being investigated.

We have no updates concerning Ocotillo.

The plan just needs to be finalized and then put into execution. We hope to have more information to share next month.

A new working group was recently formed: the Future of ARCSAT Working Group (FAWG, or “fog”) was established to review the needs/desires of the ARC community regarding past, present and future uses of ARCSAT. We expect that they will want to issue a survey of the broad ARC community concerning ARCSAT usage and desired capabilities, so the UC will be asked to help the FAWG get responses. Stay tuned!

A new page has been added to the 3.5m wiki to demonstrate the effects of satellite streaks on ARCTIC imaging. This page will be updated as more information is provided to us. If users report instances of satellite contamination we would like to know! Please have them notify Nancy. The new page is here: satellites We will also add a link to this wiki from the new web site once an appropriate place is identified.

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: OPEN. The proposal is done; Nancy needs to confirm with NMSU's Office of Grants and Contracts whether they need to be involved in the submission since it's a small proposal. She plans to submit it before the next Users Committee meeting.
• Nancy: Ensure that a short description of the impact of satellites be posted on the APO website somewhere and updated every 6 months or so. Nancy received examples of this issue from Anne Verbiscer and will get something added to the current (and new) web site. STATUS: CLOSED.
• UC reps: remind your users to review the Q2 schedule and request OPEN/DD time if they can make a good case for it. STATUS: OPEN.

New action items from this meeting: None

None

The next meeting will be on May 6, 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Ben Williams (UW), Aleksandr Mosenkov (BYU), Michael Hayden (OU), Anne Verbiscer (UVa), Moire Prescott (NMSU), Zach Berta-Thompson (CU), Joanne Hughes (Seattle U), Misty Bentz (GSU), Eric Bellm (UW), Gordon MacDonald (APO), Kevin Schlaufman (JHU)

• BYU - nothing to report
• Colorado - CU trainees are at APO right now and having a great time
• Georgia State - nothing to report
• JHU - nothing to report
• NAPG - no report
• NMSU - Moire had some questions about the ARCSAT camera - these were addressed in the Q1 ARCSAT schedule report (see below)
• Oklahoma - there was a meeting with the OU Astro group and their VPR to discuss SoonerCam - this was discussed in the instrumentation initiatives report (see below)
• Seattle - nothing to report
• UVa - nothing to report
• Washington - nothing to report
• Wyoming - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 2/05/25 – 03/03/25

1) Overview

Weather wise, it was a milder and drier than average February. There was one on-site astronomer but no instrument teams visiting APO in the month of February. The first of two groups of students from CU were scheduled for their first night on the telescope last night.

2) Operations

There is a new version of TUI available: v. 3.1.8. Visit the TUI Downloads page from the APO website for this newest version.

3.5m Telescope: Telescope is working as expected.

0.5m Telescope: Telescope is working as expected.

KOSMOS: The disperser and mask wheels have been struggling with multiple failures. We are evaluating the problem but in the meantime, moving them by hand is the quick resolution when they get stuck.

ARCTIC: Maintenance on the diffuser mechanism is scheduled for the upcoming engineering time. We have had three failed ion pumps in the past many months. We were sent the wrong model. The manufacturer recognized that this was their error and they are replacing them. Once we get the correct model in stock we will swap out the one on the instrument.

Agile: The camera is back at the repair house as the testing with APO software revealed a failure to select gain settings within the software; the demo camera they sent along for testing also did not work during recent bench testing on site. They confirmed they received the equipment we sent back. We are waiting to hear back from the repair house if both cameras work or do not work with their software and our controller.

ARCES: System is currently up and usable. There was a recent report that flat fields are shifting. The orders appear to shift a few rows from image to image. The cause is unknown at this time especially since the instrument had been so stable for years. It is advised not to use super flats in your reductions unless you carefully compare individual raw images you are combining.

DIS: System is cooled and usable.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The system is operational. The team is currently undergoing a campaign to find and receive returns off of the Next Generation Lunar Retroreflector (NGLR-1) on the Firefly Aerospace Blue Ghost Lander.

We had one on-site 3.5m user in February. The first of two groups of students from CU arrived on Sunday evening and they had their first night of training last night. Hopefully the weather will improve for them soon.

We continue to have troubles with the ARCTIC vacuum system. We warmed the camera up yesterday; today we should receive the replacement ion pumps (after the wrong model was sent to us originally). Once they arrive we are prepared to change them out and pump/cool the instrument before the next scheduled use in 1.5 weeks. We also hope to service the diffuser rotation mechanism during this down time.

Agile is back at the repair facility after lots of frustration with trying to get the camera working. It seems to perform fine while there but not at APO. We have a longer term plan for the replacement of Agile with a different camera (see below).

Other instruments are performing nominally. The KOSMOS mask/filter wheel had multiple failures during commanded moves; it gets stuck when moved often. When this happens it can be moved by hand and then it doesn't happen again for a while. Users will know when the failure takes place because it will show up as a non-completed command in TUI.

APOLLO is operational. We are trying to range to the new retroreflectors that were just placed on the Moon by the Firefly Aerospace Blue Ghost 1 lander. Lots of hard work from the APOLLO team at APO and GSFC has gone into preparing for this landing!

There is a new version of TUI available.

A user recently reported an issue with ARCES flats: their reduction software is choking on super-flats. Flats taken during the beginning of an observation may be shifted vertically on the chip compared to flats taken later during an observing session. The result is that when constructing a super flat from these multiple sets of flats, when the orders are combined the signal gets smeared out. It is not clear if the grating itself has moved or this is due to something else (e.g. a thermal effect?). Users are encourage to examine their flats, avoid using super-flats, and let us know if they see a similar issue so that we can try to diagnose the problem.

The Q1 schedule is almost full now. There are a couple of short slots still available (on Mar 19 and 22) but we have received requests for them already. We will not assign them until next week so we are still taking requests for those slots if there is something compelling or time critical.

We received everyone's requests for Q2. Amanda working to put together the schedule, which is a particularly challenging one due to multiple requests for short slots and some conflicts. It should be going out to the users next week. One concerning issue is that this quarter we received several requests for training without a lot of notice. We will try to accommodate these requests but our ability to do so decreases when we don't have a lot of advanced notice.

There is one open week remaining on the schedule, but a request was received this morning so it may actually be completely scheduled now. After the Q2 3.5m schedule goes out next week Ben will send out the Q2 ARCSAT call for proposals.

Update on ARCSAT camera: Bill changed from FlareCam to another spare we had. This has not completed resolved the library support error problems but has significantly reduced the frequency of them. It has the same pixel scale and FOV as FlareCam.

No new announcements, but lots of work is going on behind the scenes. We will remove this item from the monthly agenda and add it back in when we have something new to report.

We still have heard no news from NSF regarding the pre-proposal that was submitted for ASPEN. The UW Telescope Engineering Group has been working on their response to the Ocotillo Critical Design Review report. It will include a revised timeline, which Nancy will share with the Users Committee once the CDR Review Panel has had a chance to react. Preliminary discussions are ongoing about the possibility of replacing Agile with a more modern and capable high-speed imaging camera. There are several elements to the instrument (camera, focal reducer, computer/control software) that will require people power. This will be done on a non-interference basis with the Ocotillo development. We are preparing a white paper that describes the instrument and will share that with this group as things develop.

The general instrument decommissioning plan document is nearly complete. Once it is, it will be applied to DIS and shared with the ARC Board of Governors.

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: OPEN. The proposal is done; Nancy needs to confirm with NMSU's Office of Grants and Contracts whether they need to be involved in the submission since it's a small proposal. She plans to submit it before the next Users Committee meeting.
• Nancy: Ensure that a short description of the impact of satellites be posted on the APO website somewhere and updated every 6 months or so. Nancy received examples of this issue from Anne Verbiscer and will get something added to the current (and new) web site. STATUS: OPEN.
• UC reps: remind your users to review the Q1 schedule and request OPEN/DD time if they can make a good case for it. STATUS: OPEN.

New action items from this meeting:

• UC reps: notify your users that there is a new version of TUI that they should download and use.
• UC reps: ask your ARCES users to look at their flat fields and let the APO staff know if they see issues with changes in flats over the course of an observation.

None

The next meeting will be on April 1 (no foolin'!), 2025 at 10:30 MDT.

Attending: Nancy Chanover (NMSU), Kevin Schlaufman (JHU), Zach Berta-Thompson (CU), Aleksandr Mosenkov (BYU), Bill Ketzeback (APO), Eric Bellm (UW), Misty Bentz (GSU), Russet McMillan (APO), Anne Verbiscer (UVa), Moire Prescott (NMSU), Joanne Hughes (Seattle U), Michael Hayden (OU)

• Seattle - nothing to report
• Washington - nothing to report
• Wyoming - nothing to report
• BYU - nothing to report
• Colorado - nothing to report
• JHU - nothing to report
• NMSU - Moire has not been receiving the quarterly institutional passwords by postal mail - Bill will follow up
• Oklahoma - nothing to report
• Georgia State - nothing to report
• UVa - nothing to report
• NAPG - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 1/08/25 – 02/04/25

1) Overview

Weather wise, we had a very cold January with a mix of clear and cloudy nights. Numerous cold related problems were present in January, detailed in the following report. There were no astronomers, instrument teams or classes that visited APO in the month of January.

2) Operations

The main site generator has been experiencing a few problems since the start of the new year. Fuel contamination is suspected and we obtained some test kits to determine the cause. We are waiting for the results to see if it is bacterial or water in the diesel. A repair of some wiring was also required as the main electrical transfer switch was not sensing enough voltage from the generator to switch over on a drop of utility power. In the meantime the backup generator has been on standby.

An issue with the computer UPS occurred after a planned replacement of three quarters of the backup batteries. Batteries were only charging to a fraction of their full load and runtime was quite short. The problem has been resolved and the unit is now 100% charged with the expected hour of backup runtime should we lose all utility and backup power. This would be enough time to gracefully shutdown servers.

3.5m Telescope: Telescope is working as expected. Following a planned power outage for line maintenance by the local power company, there was a failure of a circuit breaker to the enclosure motor amplifier cabinet that prevented moving the building one night. Disassembly and cleaning the breaker the next day allowed us operate until a replacement could be obtained and installed.

0.5m Telescope: Telescope is working as expected.

KOSMOS: Experienced multiple failures of the slit viewer shutter when temperatures dipped near and below the -10C rating. We replaced the shutter with a spare. Some adjustment to guide optics was also needed as the image scale was changed during the shutter repair. Additional observing overhead was required in the meantime to center up targets using the science detector in imaging mode. The disperser and mask wheels also have been struggling with colder ambient temperatures during this time, making use of the instrument challenging during part of the colder nights.

ARCTIC: Maintenance on the diffuser mechanism will be scheduled as well given the reports of intermittent behavior at times.

Agile: The camera is back from the repair house for local bench testing with APO software for failure to software select gain settings as well as a demo camera for testing. The earlier problems with the TEC and readout of the CCD have been resolved. We are waiting to hear back from the repair house if they learned enough from the testing we did to try again to repair the camera or if we will reinstall with manual gain settings.

ARCES: One reported failure of the sky/cal mirror was reported. This certainly is another cold temperature related problem as the motor driver is at the limit of its current output. The system is currently usable.

DIS: System is currently up and usable.

NICFPS: System is cooled and usable.

TripleSpec: System is up and usable. There was one report of the main detector reading all zeros. A reset of the camera controller corrected the problem.

APOLLO: Installed a new chiller for the laser. We have ranged a few times since installation without seeing abnormal operating temperatures. The system is in operation.

The site had a few power related issues recently. There was fuel contamination in the backup generator; a wiring issue in the generator was also repaired. A full servicing of the main generator is complete and it is ready to be put into service for full back-up utility power (as of this morning). There was an issue with the computer room UPS that led to servicing in January; the batteries weren't fully charging but it is fixed now. We are investigating whether we can get that unit back on a service contract so if components fail in the future it's not as expensive for us to repair.

During a recent routine, scheduled power outage, after coming back to main utility power a breaker that controls the building enclosure controller amplifier failed. We didn't have a spare so the telescope was down for a night because we couldn't move the enclosure building. It was brought back up the next day (the technical staff worked out a temporary solution until the spare was received and put into place). Hopefully we will not be switching back and forth between generator and utility power for testing/burning off fuel too much more.

Both the 3.5m and 0.5m telescopes are working as expected. The cold weather in January led to some issues with some of the instruments (primarily with shutters). The KOSMOS slit viewer shutter was sticky when temperatures fell below its temperature rating. We replaced it with a spare and are looking to get more spares on hand. The disperser and mask wheels also were struggling in cold weather. The ARCTIC diffuser mechanism is also something that we're hoping to schedule a repair for during next engineering time. Agile is back and we're working with the repair shop on a path forward (reinstall as is or have them try to repair it further; the programmable gain still not functioning). The rest of the instruments have all been behaving nominally. TripleSpec had an issue with the detector reading zeros but a reset of the camera controller did the trick.

Misty asked if we have discussed any long-term solutions to avoiding these instrument cold issues in light of the extreme weather we have been (and likely will continue to be) experiencing. Bill answered that when we install instrumentation or spec new instruments, we try to spec them for an operating temperature of -20C. If we get down to -15C that's our de facto closure limit (because that's where the telescope itself starts having issues). However, there are some parts for which we cannot get manufacturers to give us an extended cold temperature range. But this is not something that we've spent a lot of additional time trying to find other solutions for.

We have some unassigned time in Q1 (mostly B halves) - most urgently Feb 08B, but there are a few others in February and March as well. We have received some requests for this time already but if there are any urgent requests or high priority (e.g. students) programs please let us know ASAP, otherwise we will allocate time (at least the slots in the first few weeks of February) to the people who already made requests. This time is listed as OPEN on the Q1 schedule. Users should look at the schedule and follow the usual channels for requesting this time (i.e. email Russet, Amanda, Ben, Nancy and their institutional scheduler when submitting requests, and provide a proposal cover page if you don't already have a program scheduled for the current quarter).

The allocations were sent to all institutions yesterday; proposals are due on February 24. A few items to note: (1) any users who request to use Agile in Q2 should specify a backup instrument, (2) DIS is offered in shared risk mode only and has not been serviced for several quarters, (3) the allocation emails also contain a breakdown of the split between A halves and B halves. Institutions should try to avoid requesting all of their time in A's (or B's) since we will not be able to accommodate everyone's requests if that happens.

The 2025 Q1 ARCSAT scheduled is posted. There is available time that people can request in the next week and a half, and then again in the last week of March. In early March we will have an onsite class and other stuff going on so ARCSAT is not available during weeks when the schedule is marked BUSY.

No new announcements. We are trying to resolve some recent issues related to TUI logins; lots of work is going on behind the scenes but there is no news or action items for the Users Committee this month.

We still have heard no news from NSF regarding the pre-proposal that was submitted for ASPEN. The UW Telescope Engineering Group has been working on their response to the Ocotillo Critical Design Review report; they expect to submit it to Nancy next week. There have been some preliminary discussions about the possibility of replacing Agile with a more modern and capable high-speed imaging camera. This is in the very early stages of discussion but if there are users who would want to take advantage of this capability they should contact Nancy so we can make sure that we can advocate for those science cases.

Nancy has drafted an instrument decommissioning document that she and Bill are working on. The hope is to have this general document finalized before the end of the month so that it can be applied to DIS. The first order of business will be to issue a formal notification to all stakeholders about our plans to decommission DIS.

Open action items from previous meetings:

• Nancy: get Mt. Cuba Foundation proposal for new KOSMOS grisms submitted. STATUS: OPEN. The proposal is done; Nancy needs to distribute it to the users who requested the grisms to ensure that their science cases are adequately described. She plans to submit it before the next Users Committee meeting.
• Nancy: Ensure that a short description of the impact of satellites be posted on the APO website somewhere and updated every 6 months or so. Nancy received examples of this issue from Anne Verbiscer and will get something added to the current (and new) web site. STATUS: OPEN.
• UC reps: remind your users to review the Q1 schedule and request OPEN/DD time if they can make a good case for it. STATUS: OPEN.

Open action items from this meeting:

• None.

There was a question about the development of Ocotillo (and other instruments) and whether it is contingent on getting federal funds (e.g. from NSF). This led to the question of how reliant APO is (more broadly) on federal funds. These items were discussed in light of the recent chaos resulting from the suspension of federal grant payments until they can be confirmed to be compliant with the recent Executive Orders.

The next meeting will be on March 4, 2025 at 10:30 MST.

Attending: Nancy Chanover (NMSU), Jamey Eriksen (APO), Aleksandr Mosenkov (BYU), Bill Ketzeback (APO), Eric Bellm (UW), Anne Verbiscer (UVa), Moire Prescott (NMSU), Moire Prescott (NMSU), Russet McMillan (APO), Misty Bentz (GSU), Kevin Schlaufman (JHU), Zach Berta-Thompson (CU), Sarah Tuttle (UW), Joanne Hughes (Seattle U), Ben Williams (UW), Chip Kobulnicky (UWy)

• Oklahoma - no report
• BYU - nothing to report
• JHU - nothing to report
• NMSU - nothing to report
• Washington - nothing to report
• Georgia State - nothing to report
• Colorado - the ARCTIC diffuser rotator stopped working and users are asking about the timeline for getting it repaired; one user had a weird issue with KOSMOS when it stopped taking exposures
• Wyoming - nothing to report
• UVa - nothing to report
• Seattle - nothing to report
• NAPG - no report

The detailed site report is included below, followed by additional information discussed during today's meeting.

3.5-m Telescope and Instruments Highlights, 12/03/24 – 01/07/25

1) Overview

Weather wise, December was very mild in terms of both temperatures and precipitation. There were no astronomers, instrument teams or classes that visited APO in the month of December.

2) Operations

3.5m Telescope: Telescope is working as expected.

0.5m Telescope: Telescope is working as expected.

KOSMOS: nothing to report.

ARCTIC: We performed another emergency vacuum service due to the vacuum softening. The current hypothesis for the cause of this issue is that we may have gotten/installed an ion pump that had a defective/reduced lifetime; it is still struggling to maintain vacuum. We plan to replace it ASAP with minimal or no impact to the science schedule. In the meantime, we have restricted instrument rotation to prevent the ion pump from shorting out when upside down, which seems to be a pattern. Additional maintenance on the diffuser mechanism will be scheduled as well given the reports of intermittent behavior at times.

Agile: It is being worked on at the repair house to investigate the hardware that was changed and how that impacts observing modes/gain settings. APO software control was not able to configure the camera as expected when it was initially tested at APO after the repairs.

ARCES: The system is up, however, over the holiday break there was an error indicating a failure to read images, which led to the instrument control software being restarted. That restart led to additional errors when the system recovered in an unexpected way. We are investigating this further. Science was/is not affected, this only impacted daily engineering IOL data.

DIS: System is currently up and usable.

NICFPS: System is cooled and usable.

TripleSpec: System is up and usable.

APOLLO: system leaks were repaired and the system is in operation.

Nothing to add other than what was in agenda. There is a multi-day weather system coming in tonight, which could include snow. The KOSMOS weirdness that Zach reported above has been resolved. There was an emergency vacuum servicing done for ARCTIC; the ion pump was replaced this past weekend. ARCTIC was used B half last night without issue. Russet suggested that we remove the rotation restriction for ARCTIC. The diffuser rotator repair is still to be scheduled; it was tensioned but the rotation sensor is not working properly. Agile is still at the repair shop. ARCES is back and usable after the issue with daytime metrology data described in the site report above. Russet will check with Amanda about headers not being written properly for KOSMOS; this anomaly affected Zach BT a few weeks ago.

We have some unassigned time in Q1 (mostly B halves). This time is listed as OPEN on the Q1 schedule. Users should look at the schedule and follow the usual channels for requesting this time (i.e. email Russet, Amanda, Ben, Nancy and their institutional scheduler when submitting requests, and provide a proposal cover page if you don't already have a program scheduled for the current quarter).

The 2025 Q1 ARCSAT scheduled is posted. We only had 2 requests this quarter (note added in proof: we received a third request, so there are now 3 programs scheduled to use ARCSAT in Q1). We are continuing to struggle with frequent failures in communication with the camera (which manifests as a “support library error”); FlareCam is getting old. The temporary fix is fairly quick so if observers can keep an eye on it and report errors it can be recovered pretty quickly. In early March we will have an onsite class and other stuff going on so ARCSAT is not available during weeks when the schedule is marked BUSY.

There is a plan to run a test tomorrow for converting the site to new servers (but this may be postponed due to illness).

The IT team at APO is still researching applications to improve password handling; all we know right now is that the switching of the TUI password is coming.

We have heard no news from NSF regarding the pre-proposal that was submitted for ASPEN; we hope to hear soon. Sarah reported that since having received the Ocotillo CDR report on December 2 her team has been evaluating the comments and preparing a response. They also applied for some funding and are waiting to hear back. It is clear that the instrument will come together in a phased approach, bringing the three channels online one at a time. They will start with the IFU and follow up with MOS component, which is more costly and mechanically complicated. The hope is that this would enable supported data reduction development along the way and troubleshooting as we go. It also spaces out the cost, which reduces impact on the overall observatory budget. Their goal is to have their response report back to the CDR review panel by the end of the month.

Nancy is working on developing a document that lays out the decommissioning plan for DIS. The instrument has not been serviced and will only be available in Q1 (and Q2) in a shared risk mode.

Open action items from previous meetings:

• Nancy: get ROM costs for new KOSMOS grisms. Sarah reported that she has a finalized quote from one vendor. The grism design turns out to be a little complicated, but also, costs have gone up, so these are more expensive than we expected (ballpark $20k apiece). Therefore, we need to explore potential funding sources. We have reached an impasse in terms of prioritizing the desired grism; Nancy will amass all previous emails with grism requests and send to UC reps to query users about whether there is broad interest in a particular grism. This could help identify funding sources, either individually or collaboratively. STATUS: OPEN. Nancy has started a proposal to the Mt. Cuba Foundation for several grisms and hopes to have it submitted before the next Users Committee meeting.
• Nancy: Ensure that a short description of the impact of satellites be posted on the APO website somewhere and updated every 6 months or so. Nancy received examples of this issue from Anne Verbiscer and will get something added to the current (and new) web site. STATUS: OPEN.
• UC reps: remind your users to review the Q1 schedule and request OPEN/DD time if they can make a good case for it. STATUS: OPEN.

Open action items from this meeting:

• None.

None

The next meeting will be on February 4, 2025 at 10:30 MST.