TMS Meeting Minutes, March 17, 2022

Attendees: Andrew, Bo, Breann, Christian, Olga, Matthieu, Trenton, Yang (Zoom Meeting)

Meeting on April 8th:
  • Andrew forwarded info to TMS on proposed meeting agenda
  • Bo says GMTO team approves of the proposal
  • Bo states that it will be very useful to GMTO to learn about the real-world TMS experience of the team here at LBTO
  • Seems very approriate to have this sort of meeting as GMT is genetically related to TMS
  • Logistics:
    • Location
      • Two day event, Friday, April 8th for discussions, then Saturday, April 9th, for hardware visit on telescope
      • Friday: meetings will be on UofA campus (likely at Steward)
      • Saturday: on mountain
    • Cost
      • Minimal costs on LBTO side (we have meeting rooms in Steward)
      • Food and coffee should not be a problem either
    • Agenda looks good, not a lot of slides, mostly discussion between GMTO and LBTO, one small issue
      • Mistake: two items at 14:00; this will be corrected
    • Bo wonders if it would be okay to invite others, such as Brian McCloud at SAO, possibly Joel Nisson
      • Andrew suggests it could be good to find someone from LSST and possibly the Mirror Lab
    • COVID Restrictions:
      • No vaccination mandate, masks are still encouraged (required in certain situations)
    • Numbers up the mountain on Saturday:
      • Looking like around 3 for sure plus 4 maybes, so possibly between 3 and 7
      • ?? LSST and ?? Mirror Lab (maybe not going up the mountain)
      • Christian will be available to take people up the mountain
      • Should certainly give priority to those who are visiting from out of town
      • Bring a warm coat, and be prepared for the affects of altitude
    • Times
      • Leave around 8:00 to 8:30, on the mountain around noon, in time for lunch, then the tour
      • It would be good to go on the telescope and have Patricio look at the collimator mounts
      • Leave the mountain around 3:30 PM, back to Tucson around 7:00 PM

Stuff Andrew is Interested In:
  • Incident with mirror power bump (mirror dropped onto hardpoints)
    • It is possible that the collimators may have moved during this crash
    • It appears no fibers were broken
    • On only one mirror, Dx, all of the collimators were misaligned after this event
    • Note, this power bump was caused by failing UPC's
    • "The TMS is a good seismometer" - Andrew Rakich
    • John is not completely convinced that this is the complete answer
    • In a system with 18 ~stable collimators for 5 years, and then 9 misalign in one event, it could be the case that there is correlation here
    • It appears that one mirror received a harder bang than the other
    • The Dx mirror, the one that was misaligned, has most all of the collimators as the heavier, larger aperture version, while Sx, not misaligned, has lighter, smaller collimators
    • Initially, one channel missing on both Sx and Dx using the last reference after re-alignment of the Dx collimators
    • Olga felt that it would be pretty remarkable if we were able to use the last reference after this much of a gross misalignment
    • Andrew notes that these misalignments tend to be rotations
    • Andrew suggests that we arrange for a few more power bumps and be ready to take notes
    • Olga notes that we have had multiple power bumps, but it doesn't seem we have experienced this much misalignment before
  • Note about the pupils
    • Andrew hasn't had time to progress since last week
    • Bright ring is a wonder
    • When a small amount of 3rd order spherical is applied, we get pupils that appear to have Z22 in them
Olga's Updates:
  • There is interest in using TMS during science operations, as mentioned in SciOps meeting
  • We should think about how to present this to the PI observing
  • There are plans to use LBC's starting from Tuesday next week, through the AZ run starting Wednesday
  • Could be used in TMS passive if not in TMS active mode
  • John sees no problem with using the TMS active mode if all of the alignment is recovered
  • John's impression is that, even though this is still shared risk operation, there is a significant increase in efficiency when using TMS active vs. FPIA again and again
  • Christian's opinion is that TMS works very well when conditions are good and that it doesn't hurt when conditions are very bad
  • If it goes really crazy on one side, while using TMS active, can always correct and move to FPIA upon failure and obtain another data point
  • John adds the caveat that you need to pay attention when changing elevation, as it is possible to start collecting photons before TMS is done collimating
  • Olga states that, typically, co-pointing is achieved before photons are collected, which could be enough time for TMS to finish, but we should be careful
  • In this case, could lose the first image of your series of images, which could stop the run to conduct FPIA
  • Christian's states that we could make a deal with the PI's to always take a pair of images if the first one looks weird to see if TMS finishes
  • Olga notes that there is a small slew between co-pointing field and the science field, and there is some danger of TMS changing things here
  • In this case, you'll definitely need to stop your OB until the Group Rotation Vectors have stopped changing (TMS has finished)
  • John notes that to check this settling of Group Rotation Vector, you could run LBT Plot and take another 20-45 sec penalty to check for stability
  • These are subtleties in the procedure that are difficult to communicate to inexperienced OSA's

-- TrentonBrendel - 17 Mar 2022
Topic revision: r1 - 17 Mar 2022, TrentonBrendel
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