apo-wiki

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 back to working order but there may be additional work to be done to address a recent 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 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.