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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)

Russet McMillan (APO), Anne Verbiscer (UVa), Adam Kowalski (CU), Chip Kobulnicky (UWy), Gordon MacDonald (APO)

• NMSU - nothing to report; eager to hear about KOSMOS update
• Washington - ditto
• UVa - nothing to report
• Colorado - no report
• BYU - nothing to report
• Georgia State - nothing to report
• Oklahoma - nothing to report; eager about KOSMOS
• 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 (NAPG) 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.

3 class visits in Oct-Nov, upcoming class at end of this week, current training responsibilities transferred over to Russet and Amanda.

3.5m telescope - working fairy well. Still have occasional motion error (seasonal), haven't seen an increase so haven't further tuned the axis drives. Motor amp fault in tertiary; corrected by homing mirror. Pretty infrequent events but difficult to track down.

0.5m Dcam-spare - cleaned to remove water spots but without much success. Likely going to replace DIS slitviewer to use in ARCSAT. UVa camera still available. Not much luck testing BYUCam - may send to Fingerlakes for repair/evaluation.

KOSMOS - repaired cold strapping in a temporary sense - constrained wired cold straps put back in place because unable to get braided copper straps to properly silver solder. Engineering last night - did some additional dark testing to make sure that it's still holding up as a fix; some dew on cryostat window due to lack of purge air turns on when put back together, They dried up. During Q1 will warm and pull cryostat to clean window. Should flat field out in the mean time and are barely noticeable.

ARCTIC had problems with vacuum / cryostat ion pump. one instance with filter wheel unable to be commanded. Restarted hardware controller in November.

Agile not taken apart yet but have received all parts for SoonerCam but will start assembling it after first of year as well as software developing.

ARCES - reminder about FITS header DATE-OBS keyword was incorrect. Also - in last week had some intermittent THAr lamp behavior - not energized. Recent echelle users should look at their cals to confirm that cal files are not blank. DOn't think it's a bulb problem, probably cabling or power supply. Still investigating.

APOLLO - had 2 sessions in last 2 months where hit all 6 retroreflectors. And tracked down some water line problems identified and repaired.

Moire question: is ARCES value offset constant or does it depend on when data were taken? BK: thinks it's constant.

KOSMOS - plan to remake some of the parts for cryostat separately so that servicing time is minimized.

The Q4 schedule is posted. Some open/DD time available on 12/23 and NYE also open. otherwise pretty full. Also have a couple of ToO paybacks that may need to be filled in towards the end.

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.

All requests in. The Q1 schedule is in the works. Working out conflicts. Should have something around 12/10. ARCSAT call comes out late next week.

The ARCSAT Q4 schedule is posted. also open around the holidays. 2 weeks.

• 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: Putting things together. working on optics mounting, have dispersrfor red channel - stuff getting made in shop. Working to characterize and provide software for camera. Fiber ass'y in new year.

Tentative launch date of Jan 13. working on staff access for login portion. Anne V : will old site still be accessible?

xxx

xxx

MH - extremely useful; one of most valuabe stellar spectroscopy databases in world; if go this route, get pipeline EB - great idea, archive is table stakes in today's world, enhance science impact of observatory over time, worth thinking about partnerships. NOIRLAB has experience, some $$. Have strong expectation that data become public

Open action items from previous meetings:

• Nancy/Sarah: follow up with Jim Davenport about the status of PyKOSMOS and report back.

open on git hub - tutorials are not fully vetted - not locked down - open to editing

• Joanne Hughes: put the KOSMOS MOS data reduction software on the wiki. - waiting for update from College of Idaho
• UC reps: remind your users to review the Q4 schedule and request OPEN/DD01 time if they can make a good case for it.

New action items from this meeting:

• xxxx

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.

Propose same general day/time (first Tuesday of the month at 10:30 MT); push January meeting one week later? Jan 13 Feb 03 Mar 03 Apr 07 May 05 Jun 02 Jul 07 Aug 04 Sep 01 Oct 06 Nov 03 Dec 01