Overview of SSD26 Telescope Activities

The SX and DX primary and tertiary mirrors were washed during SSD26.

The observing computers were upgraded to AlmaLinux 9. This upgrade introduces new procedures for remote desktop access. Users should refer to the Remote Observing Software Setup page for details.

Instrument Status

LUCIs

Both LUCIs were removed this summer for maintenance and repairs.

Although much of LUCI1’s maintenance was completed during the April campaign, additional work on the fold mirror motor required further work this summer. This work is now complete.

LUCI1 has been reinstalled on the telescope and cooled, and functional checkouts are underway. LUCI2 remains in the lab, where checkouts are expected to begin soon. Its installation is planned for approximately September 2, 2026.

Full checkouts of both LUCIs are expected to be completed during the upcoming restart period.

MODS

Both MODS instruments have been reinstalled, and closed-dome and on-sky checkouts have been made.

Last summer, the MODS team visited and, among other things, worked to repair the MODS2 slitmask cassette. Several loose bolts were found, which could have caused a misalignment of the cassette with the V-grooves which the mask follows as it is driven into the focal plane. The cassette was realigned as the bolts were tightened. During on-sky checkout on a low-elevation field, the mask failed to go into the cassette, requiring on-site assistance to recover.  This error could not be reproduced in daytime tests made at the same orientation. Work on this issue is still in progress and updates will follow.

The detents in both MODS1 and MODS2 cassettes were inspected and repaired, returning all mask slots to service.

 

LBCs

The LBC filters and lenses were cleaned. The team also cleaned the inside surface of the LBCR cryostat window, resolving the debris issue seen in LBCR images during 2026A. Additional work was completed to improve the LBCR vacuum.

Both LBCs have been reinstalled, and functional checkouts on the telescope are complete. On-sky checkouts are planned during the upcoming restart period.

TMS

TMS installation has been delayed due to staffing constraints. Installation is expected later in September.

PEPSI

PEPSI team members were on-site in August for general maintenance and training.

PEPSI experienced a critical loss of pressure control. Replacement parts have been ordered but are not expected to arrive until mid-September. Pressure is stabilized with the solenoid valve.  Further details are available in the PEPSI pressure-control status update.

AGW8 guide cam was replaced and aligned within a few pixels.

Blue stage was refocused after annual maintenance.

We plan to complete several focal-station and checkout tasks.  PEPSI release for science is pending several calibration and checkouts.

AO

The DX ASM was removed this summer for maintenance and servicing.