TMS Meeting Minutes, February 17, 2022

Attendees: Andrew, Christian, Heejoo, John, Olga, Matthieu, Trenton, Yang (Zoom Meeting)

LBC Availability:
  • LBT-B, the German partner, has dibs on LBC at the next available time
  • However, we have a full moon now, so it won't be for a bit
Updates from this past week:
  • Two nights, 2/10 (no TMS b/c software testing by Etalon), 2/14 active TMS
  • Valentine's Day 2/14 active TMS results:
    • For the majority of the night, red side active, left side non-active, just a single FPIA run
    • Very first object was observed with blue active, red passive until about 3:00 UT
    • Gap right before 3:00 UT was caused by a run of dofpia, with blue active and red passive, Olga felt the need to run FPIA on red
    • Then, switched to red active, blue passive at ~3:20 UT
    • Change of field at 3:10-3:15
    • Big jump in red at 5:10 UT, while TMS red was running
    • Heejoo's first conclusion is that TMS doesn't appear to have caused the spike, b/c we don't see any major TMS corrections applied at this time
    • TMS ignores the pointing corrections, though it does see the pointing corrections
    • Extended, in-depth discussion on this spike
  • At the very end of the night, ran FPIA on both sides to show how much correction was required for the active red side versus the passive blue side
  • There were a lot of corrections (many iterations) in the spherical aberration from crosstalk between Z11 and Z22 on red, even after having active TMS
  • Olga notes that there was an aberration that was growing on the blue side, even when it was running active TMS
  • Andrew believes that a quick improvement on FPIA may be possible with a quick engineering run
  • By collecting images on either side of focus, ambiguities could be removed by imparting deterministic offsets in Z11, Z22, etc.
  • This could result in substantial improvements with very little effort
Shutter Testing:
  • Etalon ran a shutter control software test over the past weekend
  • Conclusion is that every distance measurement opens and closes the shutter, which can cause errors, specifically going from opaque to transparent
  • The suggestion from Etalon was to limit the number of times the shutter is open by controlling the shutter solely with the TCP/IP
  • By only opening the shutter once at the start of the night, and closing at the end of the night, this issue could be effectively solved
  • Yang's code could be updated to accomodate this requirement
  • First, we plan to test this fix by inserting the shutter controls into the data acquisition loop code with a delay
  • Operationally, could go back to leaving the laser on all the time and ensuring the TMS shutter is closed for any instrument that is sensitive to the 1530 nm light (e.g. LUCI)
Collimator Alignment on Sunday:
  • Most problematic channels have been recovered by Brian and LeRoy
  • 7 channels on Dx, 8 channels on Sx
  • 2-2-3 Dx, 2-3-3 Sx (+X, -X, +Y)
  • Heejoo suggests removing a diameter channel to equalize the distribution
  • Andrew notes that it would be good to have one measurement that's glass to glass (diameter) which shouldn't move while the upward trusses will
  • With this in mind, Heejoo will recommend we leave the diameter channel intact
  • On Monday, LeRoy and Brian plan to improve more channels
LBTO + GMTO Meetup in Tucson:
  • Let's pick a date!
  • Andrew available 3/7-3/12
  • Bo Jin planning to come from Tucson, Breann Sitarski wants to come along, and Rick D. (GMTO)
  • General interest in going to the mountain
  • Could also isolate a group of technically minded people to have a discussion on TMS
  • John alread headed up the mountain on the 9th, Saturday
  • This could be a great date for GMTO to come up the mountain
Thermal Modeling:
  • Heejoo and Trenton teaming up with Ansys/Zemax to make headway on thermal analysis of the primary mirror
  • Will be using STAR module to analyze deformation data in OpticStudio
  • Andrew to connect Trenton with his son for MATLAB Zernike fitting script, similar to Mathematica Zernike fitting notebook
  • Trenton investing time in Ansys Learning Hub to get up to speed on the software

-- TrentonBrendel - 17 Feb 2022
Topic revision: r1 - 18 Feb 2022, TrentonBrendel
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