Com20230113 - daytime AGW2 alignment

Participants: JHill, DMiller, ACavallaro, JGuerra
Telescope Support: JOrnelas

Summary

AGW2 off-axis is checked out for functionality (yesterday). Today (daytime) we did the alignment of the guide proble to the rotator center. This worked well in the daytime - better than at night if you have a way to get collimated. AGw2 is ready for use on-sky where the next operation would be to check that the transform and rotator angles are OK.

Details

AGw2 probe alignment to rotator center (first ever time done off-sky in daytime)

Situation: Telescope parked at zenith, ARGOS Calibration Source Deployed

Reference: BGTechProcedures

DX Hexapod was at X=-2.550 Y=-1.600 Z=+1.402 RX=-186.04 RY=-186.50 when telescope was collimated by the AO system. This was very convenient to have the AO collimation done by Doug, Ale, Juan Carlos. If AO wasn't available, then we would have to collimate by eye. The image was slightly defocussed, but that helped with not saturating the star image from ARGOS source (nominally 10th mage at max intensity). Images are in /lbt/data/share/tcs/lbto.20230113. Note that the edges of the rotated donut image are very sharp in the absence of seeing and telescope shake, but the resulting donut is not round. Apparently AGw2 has some flexure in the probe or the guider optics.

  • setxy -u 2 -x 0 -y 612.5
  • gcsclient readGuideCam right -e 90000 (while rotating RFBG rotator by 360 deg)
  • ---> right_guider000002 - first 90 sec image background was saturated, so had to turn off all lights including the stairwells
  • gcsclient readGuideCam right -e 90000 (while rotating RFBG rotator by 360 deg)
  • ---> right_guider000003 center = 129.0,99.5 unbin = 258,199 detxy = 275,214 hotspot = 270,238
    so the y position of the star needs to increase by 24 unbinned pixels or 1.2 arcsec, which means we need to decrease the RAD ooffset value by 600 micron (1 arcsec).
  • After fixing a math mistake John changed the ooffset value from 420202 to 419602 in the AGW2 section of /lbt/oacontrol/current/etc/oacontrol.conf (We can't blame nighttime or altitude, so we'll have to call it an old-guy math mistake.)
  • rdwrconfig -u 2
  • We did not restart GCSR here, and oac knows the new coordinates of the probe.
  • gcsclient readGuideCam right -e 90000 (while rotating RFBG rotator by 360 deg)
  • ---> right_guider000004 center = 130,103.5 BUT we forgot to move the probe to the new 0,612.5
  • setxy -u 2 -x 0, -y 612.5
  • gcsclient readGuideCam right -e 90000 (while rotating RFBG rotator by 360 deg)
  • ---> right_guider000005 center = 125,108.5 unbin = 250,217 detxy = 267,232
    We could bump it a bit more, but this seems to be within the measurement error, so we'll call it good there.
  • Stop and restart GCSR.
  • home -u 2 -m 21 for parking

-- JohnHill - 13 Jan 2023
Topic revision: r1 - 13 Jan 2023, JohnHill
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