apo-wiki

Attending: Nancy Chanover (NMSU), Kristian Finlator (NMSU), Bill Ketzeback (APO), Michael Hayden (OU), Aleksandr Mosenkov (BYU), Ben Williams (UW), Misty Bentz (GSU), Kevin Schlaufman (JHU), Anne Verbiscer (UVa), Amanda Townsend (APO), Adam Kowalski (CU), Chip Kobulnicky (UWy), Sarah Tuttle (UW), Shane Thomas (APO)

• Wyoming - nothing to report
• Williams - nothing to report (by email)
• Washington - nothing to report (by email)
• UVa - Anne is currently unable access the observing schedule on the new website and does not see a way to access the old website as was promised last month (this was discussed later in the meeting)
• Oklahoma - nothing to report
• NMSU - nothing to report
• JHU - nothing to report
• Georgia State - nothing to report
• Colorado - nothing to report
• Colgate - no report
• BYU - Aleksandr reported that a user who tried to sign up for an account on the new website discovered that BYU was not listed as an institution option (this was discussed later in the meeting)

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

3.5-m Telescope and Instruments Highlights, 12/02/25 – 01/13/26

1) Overview

The past month was a mix of excellent skies and very unsettled weather. About a third of the time was lost due to clouds, wind, and a few days when we could not open the enclosure due to an ice and snow storm.

We had one student training visit during this time period.

2) Operations

3.5m Telescope: The telescope is working quite well. We experienced one instance of collimation failure when one of the actuators for the secondary mirror did not reach or fail to move to the commanded position. The problem was corrected by homing the mirror. A moderate correction to collimation was applied during engineering last week.

0.5m Telescope: Telescope is working as expected. Dcam-spare was having issues with the CCD chamber frosting up. Even after multiple attempts, it could not be cleaned or made reliable. We pulled Dcam off of DIS and put it into service. Dcam and UVAcam are both available options for users.

KOSMOS: System is cold and stable. The instrument dispenser wheel had one instance of not moving when commanded. It was corrected by manually repositioning it. There was one night when the camera focus was not properly set, and some confusion resulted when the telescope focus seemed to be running low. It was corrected the next night. Some of the silicon wafers manufactured with slits have been damaged in their holders. They appear to have developed stress cracks from the differential thermal expansion of the aluminum holders. We are currently seeking companies that may be able to manufacture spares.

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 another instance this month of the filter wheel controller losing connection and requiring a reset. On another night, the instrument refused to take an exposure because another one was in progress that would not clear. An init resulted in a dropped upper left quad. The observer got back on the sky, using single amplifier mode. During the holiday break, a failure of the ion pump resulted in a loss of vacuum. The repair required a swap of the ion pump, putting the instrument back on a vacuum pump, a different ion pump controller, and a cable. Special thanks to Cary Smith, who came in over his time off to restore the instrument.

SoonerCam: 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, assembled, and software development has begun. The first biases using low-level commands were taken this past week.

ARCES: There was an intermittent failure of the thorium argon lamp power supply, resulting in lamp dropouts or weak lines. Cleaning the rheostat that controls the adjustment of amperage was a temporary fix until we can possibly repair it with a new part.

DIS: System is powered down and warm. Decommissioning plans have begun. The instrument has been decabled, and we will be lowering it off the observing floor soon.

NICFPS: System is cooled and usable.

TripleSpec: System is cooled and usable.

APOLLO: The instrument is usable for laser ranging. The team has experienced a streak of poor weather and software connection issues over the past month.

There was one student group that visited last month. We've had some winter weather and were closed for two nights due to ice on the enclosure and lightning arrestors.

As for instruments, both KOSMOS and ARCTIC each had some problems last month. There was an instance when the KOSMOS disperser wheel was commanded it got stuck; this was remedied by the operator going up to the observing level and moving it by hand. We had one instance where the camera focus wasn't set properly and caused confusion regarding the telescope focus; this was corrected. We've seen some stress cracks in the UW-manufactured silicon wafer slits, likely due to differential expansion of the aluminum holders. We are working to identify a manufacturer for new spares/replacements.

ARCTIC had a failure of the filter wheel; this was discovered by an observing specialist in the afternoon and fixed by the engineering staff that same day so it did not impact observing. We had another instance where the instrument exposure was stuck and could not be commanded to take another. An init was done, which caused a dropped quad, and the user elected to observe in the single amplifier mode for the rest of night. We had a more serious issue with an ion pump that resulted in loss of vacuum to the instrument. This was due to a failure of a high voltage cable that became welded to the pump; both needed to be replaced. Special thanks for Cary Smith who came in during his time off during the winter break to restore the instrument.

First biases were achieved with the new SoonerCam setup. We are starting to develop the new ICC software and trying to learn the lower level commands for triggering the camera.

We've seen an intermittent failure of the ARCES ThAr lamp power supply, We cleaned the connectors and this seemed to help but the issue still sporadically appears. Users should check their ThAr exposures to make sure they have enough lines with appropriate S/N levels.

DIS decommissioning continues; the instrument is decabled but still on the observing floor for now.

There have been no issues with TripleSpec or NICFPS, and APOLLO has been working well.

We have completed hiring process for a new Support Astronomer (observing specialist). Harrison (Harry) Abbot will begin his work and training in a few days.

There will be a site infrastructure review held at APO next month. The goal is to review overall site and telescope infrastructure items (excluding instruments) in order to develop priorities for resource allocation in order to ensure that we maintain a highly functioning observatory.

The Q1 schedule is posted. There is some OPEN time available on Jan 18A and also in February and March. Users interested in requesting any of that time should send the request (including a program ID if the project already has been assigned time this quarter, otherwise a short proposal) to Ben, Nancy, Russet, Amanda, and their institutional schedulers.

The ARCSAT Q1 schedule is posted; there is one open week remaining at the end of the quarter.

• SoonerCam: See above site report and subsequent discussion.
• KOSMOS grisms: our proposal requesting funds to support the purchase of three new grisms for KOSMOS was not selected. We will move forward with the purchase of one or two grisms using ARC funds. If users have an opinion about this they should complete the following form no later than Friday January 30.
• ASPEN: we have an NSF proposal pending but learned that we did receive some funds from the State of New Mexico to further advance the design. We will move forward with building the atmospheric dispersion corrector first since it can be used with ARCES. We presented a poster about ASPEN at the Jan. 2026 AAS meeting and received some positive feedback, and we submitted several papers about the instrument for the SPIE conference this summer. We still plan to hold the Preliminary Design Review in the first half of 2026, likely now in Q2.
• Ocotillo: Things are progressing; we have the camera in hand and someone is working on camera characterization and software. We have the grating, some optics, and the fiber in hand. The TEG will be hiring an engineering/technician at the BS/MS level very soon; interested parties should look for the job ad on the UW hiring site shortly.

We flipped the switch this morning so that https://mainapo.apo.nmsu.edu became https://www.apo.nmsu.edu. This resulted in some preliminary problems as some certificates needed to be updated in order to preserve the old web site (which will be located at legacy.apo.nmsu.edu). We hope to have these sorted out by the end of the day. The links to the observing schedules are currently not working, but one can still access the Q1 schedule using this direct link: http://35m-schedule.apo.nmsu.edu/2026Q1.shtml. Shane will fix Aleksandr's reported issue ASAP. If users have difficulties finding what they need on the new site please let us know ASAP!

We had a booth alongside SDSS and SciServer so there was a strong APO presence at the Jan. 2026 AAS meeting in Phoenix. We were well positioned in the exhibit hall and received a lot of foot traffic; we gave away a lot of swag.

Open action items from previous meetings:

• 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. Update: Nancy connected with the folks working on this while at the AAS meeting so we are getting closer to have this software in hand and made available to the user community through the wiki. Status: OPEN.
• 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). No UC reps reported any feedback from users so we will be moving forward with piloting this as a next step. Status: CLOSED.

New action items from this meeting:

• UC reps: remind your users to review the Q1 schedule and request OPEN/DD01 time if they can make a good case for it.

None.

The next Users Committee meeting will be on Tuesday February 03 at 10:30 MST.