UT 20130513 Technical Observing - Active Optics Calibration

Observer: DMiller, JHill, OKuhn (Tucson)
Telescope Operator: SAllanson (LBTO)
AO Support: JCGuera (Home)
Telescope Support: JUrban (LBTO)
Instrument Support: JMorris (LBTO)

Summary (from Doug M the following day)

We measured new collimation and pointing model values earlier last evening and I put these into the appropriate configuration files (see below for specific file names).

We collected three sets of field data with some binodal astigmatism changes, however, the seeing ranged from 1.0" to 1.3+" during data collection. These poor quality data do not allow my analysis to determine which set minimizes the binodal astigmatism. Olga collected MODS image with initial alignment (ie no change in the binodal astigmatism parameters compared to the values used for the Adaptive Secondary) and found round images when the telescope was collimate with three different off-axis guide stars.

Thus I have installed the pointing and collimation values from the initial alignment in to the pt and col model files used for MODS.

The marginal quality of the field data taken last night shows that the binodal astigmatism is not bad, but in improved seeing conditions there may be astigmatism seen in MODS acquisition image. If this is the case, we may have to acquire another field data set in better seeing conditions to properly adjust the positions of the secondary to minimize binodal.

% cd /home/telescope/TCS/Configuration/PSF
% cp SXSMMODSCollimation.dat SXSMMODSCollimation.20130202.dat
% emacs -nw SXSMMODSCollimation.dat

Modified X=-3.639 (from -1.89), Y=-3.356 (from 0.0), Z=-4.0 (from 0.0) RX=70.771
+(from 0.0) RY=-572.706 (from -318.5)

Saved

% cp SXSMMODSCollimation.dat SXSMMODSCollimation.20130513.dat


% cd /home/telescope/TCS/Configuration/PCS
% cp PCSInstrument.conf PCSInstrument.20130202.conf
% emacs -nw PCSInstrument.conf

Modified for MODS LEFTPOINTINGMODEL	  SX_Gregorian.20130513.ptmod  (from
+SX_Gregorian.20130202.ptmod)

Saved!

% cp PCSInstrument.conf PCSInstrument.20130513.conf

% cp SX_Gregorian.20130202.ptmod SX_Gregorian.20130513.ptmod
% emacs -nw SX_Gregorian.20130513.ptmod

Modified IE=-94 (from -96), CA=-56.3 (from -49.3)

Saved!

Thus, to revert back to the previous pt and col values:

in /PSF dir:

cp SXSMMODSCollimation.20130202.dat SXSMMODSCollimation.dat

in /PCS dir:

cp PCSInstrument.20130202.conf PCSInstrument.conf

Details

09:20 Start collection of MODS images with different GS's at different rotator and off-axis positions

AGWX and AGWY positions are in headers as AGWXGP and AGWYGP, rotangle in header as ROTANGLE

BS9177 GS mods1b mods1r UT AGWXGP AGWYGP ROTANGLE comments
25 3 3 09:35 0.29 -184 -174 objectname incorrect (off-axis). teardrop to +Y, collimation started to fall apart after MODS images were taken, collimate on axis before next gs
21 4 4 09:51 0.225 -168 -144 images look round, fwhm~6
20* 5 5 09:58 0.18 -168 -234 *gcs picked wrong star, gs faint, image maybe very slightly elongated upper left/lower right, fwhm ~6.5
24 6 6 10:07 0.249 -179 -164 round but FWHM ~ 7.8, much worse --- taking another pair
24 7 7 10:10       up/down elongated and FWHM ~ 6.9
17 8 8 10:18 0.124 -156 -62 looks round

10:24: Steve making corrections based on analysis of field aberration data. These used the best data - the data were noisy as seeing was varying during collection of field data - from <~1" to sometimes ~1.5" .

Field Analysis with 4 points:

 => New Field Data Results
             Measured bi-nodal astigmatism
              From Astigmatism Measurement
                  On-Sky Arcseconds
         -------------------------------------------
          Tip =  -1.0", Delta IE =   1.0"
         Tilt = -12.7", Delta CA =  12.7"
  
                M2 Mis-alignment 
             M2 Arcseconds and Millimeters
         -------------------------------------------
          Delta RX =   -10.", Delta Y = -0.051 mm
          Delta RY =   125.", Delta X =  0.651 mm

Field Analysis with all points

 => New Field Data Results
             Measured bi-nodal astigmatism
              From Astigmatism Measurement
                  On-Sky Arcseconds
         -------------------------------------------
          Tip = -10.7", Delta IE =  10.7"
         Tilt =  -9.7", Delta CA =   9.7"
  
                M2 Mis-alignment 
             M2 Arcseconds and Millimeters
         -------------------------------------------
          Delta RX =  -106.", Delta Y = -0.549 mm
          Delta RY =    96.", Delta X =  0.497 mm

Initial set of SXM2 alignment corrections
IE =  -96;   CA = -49.3
IE =  -94;   CA = -56.3  (after pointing tweak)

        Glob      Man       ActO       Total
X  =   -1.890 -   0.817 -   0.932 =   -3.639
Y  =    0.000 +   3.166 -   6.522 =   -3.356
Z  =   -4.000 +   0.000 +   0.000 =   -4.000
RX =    0.000 - 608.838 + 679.609 =  +70.771
RY = -318.500 - 157.119 -  97.087 = -572.706

First set of SXM2 binodal-corrected alignment corrections
IE =  -94;   CA = -43.3

        Glob      Man       ActO       Total
X  =   -1.890 -   0.153 -   0.250 =   -2.293
Y  =    0.000 +   3.166 -   6.273 =   -3.107
Z  =   -4.000 +   0.000 -   0.038 =   -4.038
RX =    0.000 - 608.838 + 653.654 =  +44.816
RY = -318.500 -  29.460 -  26.016 = -373.976

11:00 collected 4 data points with delta Tilt = -13 dir: field_2

 => New Field Data Results
             Measured bi-nodal astigmatism
              From Astigmatism Measurement
                  On-Sky Arcseconds
         -------------------------------------------
          Tip =  -3.3", Delta IE =   3.3"
         Tilt = -13.1", Delta CA =  13.1"
  
                M2 Mis-alignment 
             M2 Arcseconds and Millimeters
         -------------------------------------------
          Delta RX =   -33.", Delta Y = -0.169 mm
          Delta RY =   129.", Delta X =  0.669 mm
 

11:05 Steve added -27 Tilt, +27 CA for a total of -40 Tilt and +40 CA dir:field_3

Second set of SXM2 binodal-corrected alignment corrections
IE =  -94;   CA = -16.3
IE = -101;   CA = -11.3 (after pointing tweak)

        Glob      Man       ActO       Total
X  =   -1.890 +   1.226 -   0.378 =   -1.042
Y  =    0.000 +   3.166 -   6.433 =   -3.267
Z  =   -4.000 +   0.000 -   0.010 =   -4.010
RX =    0.000 - 608.838 + 670.412 =  +61.574
RY = -318.500 + 235.679 -  39.413 = -122.234

~11:40 Steve added -20 tip, +20 IE

Field results

 => New Field Data Results
             Measured bi-nodal astigmatism
              From Astigmatism Measurement
                  On-Sky Arcseconds
         -------------------------------------------
          Tip = -10.4", Delta IE =  10.4"
         Tilt =  -6.2", Delta CA =   6.2"
  
                M2 Mis-alignment 
             M2 Arcseconds and Millimeters
         -------------------------------------------
          Delta RX =  -103.", Delta Y = -0.533 mm
          Delta RY =    61.", Delta X =  0.318 mm

Third set of SXM2 binodal-corrected alignment corrections
IE =  -81;   CA = -11.3

        Glob      Man       ActO       Total
X  =   -1.890 +   1.226 -   0.381 =   -1.045
Y  =    0.000 +   4.188 -   6.624 =   -2.436
Z  =   -4.000 +   0.000 +   0.003 =   -3.997
RX =    0.000 - 805.237 + 690.229 = -115.008
RY = -318.500 + 235.679 -  39.731 = -122.552

Only measure one star before sky got to bright

-- DougMiller - 13 May 2013
Topic revision: r8 - 17 May 2013, JohnHill
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