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Attending: Nancy Chanover (NMSU), Bill Ketzeback (APO), Joanne Hughes (Seattle U), Anne Verbiscer (UVa), Aleksandr Mosenkov (BYU), Misty Bentz (GSU), Jamey Eriksen (APO), Eric Nielsen (NMSU), Mukremin Kilic, (OU), Eric Bellm (UW), Kevin Schlaufman (JHU), Sarah Tuttle (UW), Ben Williams (UW)

• FGCU - nothing to report (submitted by email)
• NAPG - no report
• Seattle - Joanne is talking with Bill about using SDSS images to make masks for KOSMOS; she had been using DSS images and found that the alignment stars had too much proper motion
• JHU - nothing to report
• Georgia State - nothing to report
• UVa - nothing to report
• Oklahoma - nothing to report
• NMSU - nothing to report
• BYU - nothing to report
• Washington - nothing to report
• Colorado - 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, 10/03/2023 – 11/06/2023

1) Overview

October was a welcome busy month at APO. The telescope has continued to work well since the shutdown. The weather has been very nice as well. Humidity and storms are starting to pick up and temperatures are starting to drop.

Mid-October saw back-to-back class visits from NMSU and UVa. Both were large classes and filled up APO housing. We also had the visiting instrument DSSI on the telescope before the classes started.

2) Operations

3.5m Telescope:

- There is an occasional motion error during slews. So far no reports have been received about motion errors while tracking.

- A new pointing model was implemented after an engineering night because of a pointing shift that occurred. The source of the pointing shift is being investigated.

0.5m Telescope: The telescope is working with the reduced filter set in the loaner filter wheel.

3.5m Instruments:

The KOSMOS disperser wheel motion issues were tracked down and repaired, along with lead screw nuts on the cal stage. Some locking nuts on the instrument cart were also repaired. There have been no reports of issues since the repairs were completed.

The servicing of ARCTIC's diffuser rotation mechanism was postponed and has not yet been rescheduled.

Agile remains unavailable due to a failure of the TEC controls. Attempted repairs have so far been unsuccessful.

Echelle interorder light ratios (measure of scattered light in the instrument) are still excellent.

DIS scattered light on the red camera is currently very good; on the blue camera it had been improving but now it seems to be leveling off.

October was busy with 2 classes and a visiting instrument team on site. A BYU class is coming in November. The weather has been pretty good lately. We are still working on how to recover from the Agile failure. Some repairs were done to KOSMOS, as detailed in the accompanying site report. The observatory staff is recovering from hosting the ARC Board and SDSS AC meetings at Sunspot/APO last weekend. We had great eyepiece viewing for the SDSS AC and Board members on Friday evening; Candace did a great job playing tour guide with Amanda's help. Muk asked about what work is being done specifically regarding an Agile recovery. Bill reported that the Princeton Instruments camera is obsolete and spare parts are not available. Without an electronics person on staff we are currently at a roadblock in terms of reviving current camera. We have started to evaluate new commercially available cameras that could serve the same role; we might be able to get a loaner from Andor.

Nancy recapped the Board meeting (attendees, purpose, presentations that are verbally given and provided to the Board members as reference material, etc.). She shared some of the slides presented to the Board: 2023_3.5m_report_-_for_users_commitee.pdf

Kevin asked why the median seeing value for the ecam measurements was better (smaller) than that for all of the optical instruments combined. Nancy checked with Russet after this meeting, who said I found ecam to be reasonably representative of the visible-light instruments, a little worse than ARCTIC, comparable to Agile and NA2 guider, better than dcam. But nowadays our visible-light log statistics are probably dominated by kcam, which does have re-imaging optics for the slitviewer that make the seeing look worse. That could also account for the broader peak of the night-log statistics. A quick check of the KOSMOS tab from the seeing statistics says that yes, there are only 5 sub-arcsecond log entries for KOSMOS from the whole year.

We have a some unassigned time (OPEN or DD02) remaining in Q4. Please follow the usual channels for requesting any of this time (i.e. please email Russet, Amanda, Ben, Nancy and your 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 institutional allocations were mailed out recently, and proposals will be due shortly before Thanksgiving.

There is not much open time remaining in the Q4 ARCSAT schedule.

APO will once again have a booth at the January AAS meeting; in 2024 the meeting will be in New Orleans. We hope that many 3.5m users will present results enabled by observations made at APO, and that we can get some help staffing the booth.

Nancy reiterated that if we want to do something to celebrate the 30th anniversary of APO in 2024, we need to start planning soon. This was discussed at the ARC Board meeting but no final decisions were made.

Open action items from previous meetings:

• None

We received a request for observations of T Coronae Borealis (T CrB), a recurrent nova; the next eruption is expected to be in Q1-Q2 2024! See this page for more details: https://www.aavso.org/news/t-crb-pre-eruption-dip. The head of AAVSO contacted us to ask if anyone could take NIR spectra, which would be particularly useful.

The next meeting will be on December 5 at 10:30 MST.