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RFBG Performance Verification: 27 December 2010 UTC

Observer(s): RGreen, DMiller (LBTO)

Telescope Operator: DHuerta (LBTO)

SW Support: (Tucson)

Telescope Support: (LBTO)

Instrument Support: (LBTO)

Summary

Variable clouds and seeing between 2-3". Andrew studied the effects of range-balanced collimation model while we tried to get a second pointing model. Because of the non-modeled strong astigmatism of the adaptive secondary, collimation is required for essentially every star in the pointing grid.

Details

02:00 Telescope open after some clouds at sunset Wind 16 m/s, Temp -3C, Humidity 86% and rising.

02:10 Star BS9107 found about 15" from the hotspot. Set IE=20, CA=-25

02:21 Collimated to 200nm in about 4 iterations. FWHM on guider is 2-4". Ouch

03:00 Closed due to high humidity. Did not collect any data while we were open because of the poor seeing. Crunching data instead.

08:00 Open because humidity dropped. Installed Dave T.'s new pointing model /home/telescope/TCS/configuration/PCS/IRTC_RFBG.20101226.ptmodel. Added a CA 0.0 0.0 line so we could adjust the position of the point model. David loaded the ptmod on the PCS gui.

08:03 preset in ACQUIRE to BS9143, set IE=16, CA=4. Elevation was 56 - seeing ~2".

08:10 Collimate in 3-4" FWHM to improve focus. Andrew had David set M2 global z from -0.4 to -0.3 (Active Optics had 1 um of z) and clear Active Optics.

08:18 preset in ACQUIRE to BS9143 Elevation 37. Star is 2" from hotspot

08:20 preset in ACQUIRE to BS9133 Elevation 30. Star is 3" from hotspot

08:23 preset in ACQUIRE to BS9116 Elevation 49. Star is 5" from hotspot

08:26 preset in ACQUIRE to BS9122 Elevation 37. Star is 6" from hotspot

08:29 preset in ACQUIRE to BS9126 Elevation 87. Star is 8" from hotspot

08:34 preset in ACQUIRE to BS9142 Elevation 59. Star is 5" from hotspot (original star from 08:03)

09:40 Starting pointing model; preset to ACT0361, datacube 094506. Second preset got no star; thick cloud and humidity coming in. Closing again.

10:22 Reopening after clouds leave and humidity drops.

10:27 First pointing star - WT10_350, cube is 102640. seeing 1.5-2.0

10:39 three attempts on ACT0402 - 103920 is correct data cube, because of clouds. First ones could be used for flats.. 10:47 failed - IRTC left in movie mode and could not take cube. 10:51 Star at El=29 not visible - probably thick cloud. No data cube.

11:20 Collimation on ACT0114 diverged (low elevation, cloud, appaling seeing). Compounding the problem is the fact that currently GCS defaults to correcting focus and coma only when the wavefront is worse than 1000nm. However, with the new collimation model most of the initial aberration on RFBG is astigmatism from the M2. See issue trak 3083 suggesting a change to the GCS config file for RFBG so that when the 1000nm limit is reached only focus and astigmatism are corrected (not the current focus and coma).

11:27 - two data cubes for same star - first probably saturated.

11:44 three data cubes - first two are blank because of clouds; Third OK at 11:46, although faint with one-second exposures.

11:50 first data cube saturated. 1151 OK

11:54 & 11:55 1 second and 2 second are blank. Thick cloud, and seeing no better than 2" when stars are visible.

Should be 14 pointing stars in total to here.

12:30 Good pointing star at El=80. preceded by another OK one.

13:00 Andrew tested the IRAF rangebal routine and found a problem with the RY balancing. He's going to look over his equations and try to find the problem. This will mean we will probably have to take another set of pointing model data.

13:37 Doug tested a new ptmodel_collect.pro IDL routine to semi-automatically collect pointing model data. Had to set IE=14, CA=-1 to center the on-axis star.

13:45 Closed for impending sunrise.

-- DougMiller - 23 Dec 2010
Topic revision: r9 - 28 Dec 2010, RichardGreen
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