Science News
LUCI2: Displaced G200 Spectra
Posted Apr 16, 2024
The LUCI2 G200 grating has been having increasing trouble reliably reaching the central wavelength requested. Users/observers should frequently check the grating position for both science and calibration exposures by comparing to known good data or between LUCI1 and LUCI2. Troubleshooting notes and recovery suggestions have been added to the LUCI pages (here). If the problem persists after trying to recover, it may be necessary to switch to programs not using G200. The problem could be in the external electronics or the internal tilt sensor at the grating. Testing to determine this should be done in the next few weeks.
Note that the G210 grating is unaffected by this problem. Programs using the G200 grating in LUCI2 could be redesigned to use G210 instead, with the obvious trade-off of higher reliability of G210 vs. extra time to observe two bands for programs that require the full wavelength coverage.
LUCI1 offline – FM4 motor not moving – Resolved
Posted Jan 20, 2024
Resolved: LUCI1 Offline – Failure of FM4 motor
LUCI1 is again available for science observations. Some additional exercising of the fold mirror tilt mechanism appears to have freed up motion. We don’t see any dropped steps in either direction now. It is not possible to know for sure what the problem was without opening LUCI1, but for now that does not seem to be necessary. LUCI1 has been re-aligned to the telescope and released for science observations.
Was: On Friday Jan 26, LUCi1 experienced a failure of the camera wheel. This was quickly resolved the following day by our instrument support staff by increasing the drive current. However upon resolution, it was found that one of the fold mirror #4 motors remains unmovable. This motor is used to align the field of view on the detector. This issue is actively being worked on but LUCI1 will remain offline until resolved.
DX AO in Cold Conditions
Posted Jan 06, 2024
DX in Cold Weather – Update (Jan 6 2024)
The failure is linked to the cooling temperature at the adaptive secondary. The cooling setpoint was slightly adjusted to provide additional leeway while maintaining the safety of the adsec and neighboring systems.
For the safety of the system, DX AO operations should be halted if the chamber temperatures fall below -6C.
Nov 27, 2023 – DX in Cold Weather
Last February we experienced a number of failures of the DX AO at cold temperatures. At temperatures below -5C, there has been a high frequency of communication failures. The main signature of these failures is that the FastDiagnostics data stop being received by the DX ASM control computer. The result of this interruption is that the control computer forces a DISABLE_COIL which rests the shell and stops DX AO operation. The issue causing this particular failure remains unresolved at this time, and for the safety of the system operational restrictions have been put in place.
For the safety of the system, DX AO operations should be halted if the chamber temperatures fall below -5C.
The team continues to review data to investigate the precise temperature threshold of these events, as well as if other environmental or operational factors (such as loop frequency) may play a role. An off-telescope intervention will likely be required to fully resolve this.
DX LUCI Pyramid Rotated – Resolved
Posted Dec 15, 2023
2023-12-15 DX LUCI Pyramid Rotated – Resolved
The DX SOUL LUCI Wavefront sensor underwent a series of checkouts and performance checks on 2023-12-14. The results were analyzed and showed that the performance of the WFS is comparable to before the pyramid rotation and fix. Sample results can be seen here:
Test with Bin 1, 1544 Hz, simulated 1.0” Seeing
DX SOUL-LUCI is released for both Full AO and ESM AO.
2023-12-12 DX LUCI WFS Unavailable Update
Efforts on telescope to rotate the pyramid back into position were successful. The pyramid was rotated within 0.5 pixels of previously alignment. Additional testing and verification are pending.
2023-12-11 DX LUCI WFS Offline Update
The AO team was able to characterize the pyramid rotation issue, and with correspondence with the team in Arcetri, have determined a route for repair that can take place on telescope. This route will not require the removal of LUCI2 and will be minimally evasive. As this repair and corresponding calibrations take place, LUCI2 AO and ESM will remain offline.
2023-12-04 DX LUCI WFS Offline
On UT2023-12-04, it was found that the four DX pyramid pupils were rotated 45 degrees on the OCAM display. Further investigations showed that the pyramid is rotated in regard of the W board direction. To resolve this issue, the pyramid needs to be rotated in its housing during an intervention in the lab.
For safety reasons concerning the SOUL-LUCI AO WFS, the RFBG rotator is being locked out until the components inside the W unit are in a safe state. A trip is planned for 2023-12-05 to secure the pyramid.
Once secured, LUCI2 will be available for seeing-limited operations only until a more extensive intervention can be completed. This issue does not impact the ASMs, so it’s not limiting AO with other instruments (LBTI) or seeing limited operations. Only LUCI2 AO/ESM operations are impacted.
LUCI1 Offline for Camera Wheel Failure (Resolved)
Posted Nov 29, 2023
Update Dec 8, 2023: LUCI1 released for science…with caveats!
LUCI1 is again available for science…with caveats, so please read this carefully. We are assuming that the flexure calibrations taken prior to the camera wheel failure are still valid. We are also still using old wavelength calibrations. Neither should be particularly bad, but please keep an eye on things as you observe and make adjustments as needed. As new calibrations are obtained they will be implemented. Thus the normal observing modes for LUCI1 are available: seeing-limited or ESM imaging or spectroscopy. Full AO imaging will require recalibration of the non-common path aberrations as those changed by quite a bit due to refocussing of the N30 camera. Recalibration is continuing apace and further updates will be added here.
Update Nov 30, 2023: LUCI1 Reinstalled
The camera wheel repairs were completed. LUCI1 passed a cold functional checkout and was reinstalled today on the telescope. Functional checkouts are underway and recalibrations are pending. On-sky checkouts are scheduled for Dec 7th.
Update Nov 13, 2023: LUCI1 off the telescope for repairs
LUCI1 was warmed on telescope and removed on Nov 20th. Repairs to the camera wheel as well as to filter wheel 2 are planned for early this week. LUCI1 will then be cooled in teh lab with installation planned for Nov 29th. We will continue to update about the status of availability, including the progress with the repair, checkouts, and recalibration efforts.
Update Nov 13, 2023: LUCI1 offline
On telescope troubleshooting efforts have revealed that the issue with the camera wheel is internal to the instrument. The instrument will have to be warmed and removed from the telescope for repairs. LUCI1 is offline until further notice.
Update Nov11, 2023: LUCI1 Offline-Camera Wheel Failure
Camera wheel has failed in the N30 position. Troubleshooting efforts to move it have failed. On-site efforts will take place in the coming days. Until this issue is resolved, LUCI1 is offline.
LUCI1 and LUCI2 2023B restart delays (Update Nov08)
Posted Nov 04, 2023
UPDATE (Jan 31, 2024)
Both LUCIs are available for all normal observing modes:
UPDATE (Nov 4, 2023)
LUCI1 is now released for science for the following modes:
- N375 Imaging
- N1.8 G200 Spectroscopy
The N1.8 G210 calibration data is pending further analysis but we expect to release soon. Similar to LUCI2, LUCI1 AO is pending SOUL calibration work.
UPDATE (Nov 1, 2023)
LUCI1 was mounted on the telescope on Oct 26th. A functional checkout of the mechanisms, including the MOS unit, was performed, and it passed, although with a couple of issues: 1) Filter Wheel 2 was tending to fail frequently, though it can be recovered with care to insure that it indeed has reached the desired position; and 2) the flexure compensation fold mirror was not moving in the Y direction. Yesterday, the current to this motor was increased and it is now working, so the checkout is proceeding. Currently, we are working on collecting data for the passive flexure compensation lookup tables.
Before it is released for science, new passive flexure compensation tables need to put in place and verified; focus offsets need to be measured and implemented; the grating tilt calibration needs to be checked (quick look suggests this is good) and the AGW stage-to-sky transform needs to be measured. LUCI1 was used on-sky last night and these data will help us assess the quality of the transform that is in place.
Work is continuing to take and analyze data,
UPDATE (Oct 22, 2023)
LUCI2 released for SL science with restricted modes
LUCI2 is released for science observing in these modes with the following caveats:
- N375 Imaging
-
N180+G210 Spectroscopy
-
N180+G200 Spectroscopy
- N30 Imaging
Caveats:
- N30 Imaging is pending updated NCPA tables and AO checkout. This is being worked on this week with on-sky checkouts scheduled Oct 30th and 31st.
- N375 FlexComp is still running on the old tables. They may not be perfect, but for the usually short exposures it should be OK.
- None of these new calibrations have been “checked” yet. If you notice something off, please let us know. We are working to verify data in the coming weeks, but are shifting priorities to LUCI1
- G200 appears to still have the offset problem described in IT#7487. This means the wavelength calibrations could be off.
LUCI1 is cooling in the lab now and is expected to be installed on the telescope Oct 25th or 26th.
UPDATE (Oct 1, 2023)
The leak on LUCI2 was repaired and the instrument cooled. After cooling, the instrument failed functional checkout. The pupil viewer used to align LUCI to the telescope was failing to move completely into position. Problems were also experienced with the grating turret and filter wheel 2 during this checkout. The instrument is being warmed for repairs.
LUCI1 and LUCI2 remain unavailable.
UPDATE (Sept 18, 2023)
LUCI1 was cooled down after undergoing the repairs and installation of the G040 grating. The warm checkout of all motor functions fully passed checkouts and inspections. Once cooled it underwent the standard cold checkout where a critical failure of the Fold Mirror 4 motor was found. This motor is used for both flexure compensation and pupil and field stop alignment. Extensive efforts were made to try and resolve with the instrument cold, but the problem has been determined to be internal to the instrument. LUCI1 will be warmed and further troubleshooting to take place once warm.
LUCI2 is in the lab and undergoing repairs for the leak discovered at the end of SSD23. These repairs involve the replacement of 1-2 coldhead cylinders. LUCI2 will be cooled in the lab, and has a planned installation date of early next week.
Both LUCI’s remain unavailable.
Both LUCIs have experienced delays coming out of SSD23 that will impact their availability early in the 2023B semester (Aug 29, 2023)
LUCI1: We confirmed that the G040 grating for LUCI1 was manufactured with the blaze 180 degrees from what was designed. Newport/Richardson has thankfully expedited the re-manufacturing of the grating on the existing substrate and it has been shipped back to LBTO. ETA for delivery is currently Friday September 1.
LUCI2: The initial pump down and starting the cryo-coolers on the telescope went well but the pressures immediately started rising, indicating a leak. LUCI2 was re-warmed and leak-checked. Small leaks around two electrical pass-through connectors were sealed with vacuum putty but there appears to still be a leak we suspect is coming from one of the cold head cylinders.
In both cases, the repair or re-installation work plus pumping and cool-down pushes the availability of both LUCIs out to the end of our on-sky re-start period. One or both LUCIs may not be available, or completely recalibrated, for the early science blocks in 2023B.
