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)

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