Range Balancing LBC: 27 November 2010 UTC

Observer(s): John Hill, Andrew Rakich (Tucson)

Visitors(s):

Telescope Operator: DHuerta (LBTO)

SW Support: Chris Biddick (Tucson) plus Tony, Stephen, Norm, Michelle

Telescope Support: JLittle (LBTO)

Instrument Support: JMorris (LBTO)

Summary

Because of the cadence of software testing with Rome, the first half of the night was spent testing range balancing for LBC and then collecting pointing model data for the range-balanced LBC collimation models.

The good news: range balancing works, and makes a significant improvement to the open-loop LBC collimation. We've got plenty of range in X and Y at all elevations.

The bad news: range balancing hasn't cured all the collimation issues. There are still significant Y-coma terms generated by thermal gradients on the C-Rings. Andrew and John had a fun discussion about what causes the ~2000 nm of residual Z7: a modified zero-coma point for the LBC correctors, temperature gradients, extrapolation in the collimation model fits, or evil spirits. Andrew is becoming convinced that the "thermal gradient demon" is a real beast! (EDIT: Not yet I'm not...).

As soon as somebody reduces the 33 stars of pointing model data, the range-balanced LBC collimation models are ready to use for science. They are not yet co-pointed.

Second half of the night was used for LBC software testing with the patched BP7 build. We were closed down by high winds at midnight, so these were closed dome tests.

Preparations

Re-booted LBC control at 00:45
Turn on LBC at 00:50
Running under Build AO5 with MOD-AO2 libraries

Details

00:30 Open. Seeing ~ 1.5".

01:00 Preset ACT0364 - First LBC FPIA pupils nice and round with no coma, still to bright to fit pupils. EL 67.

01:01 Start pointing logging - 20101215.ptlog

01:02 dofpia, waiting for twilight to fade

01:14 data files did not appears in fast enough time in /newdata (dofpia complains)

01:24 Preset WT10_404

Collimation at Different Elevations (See tables below)

01:30 Go to EL 20 degrees (original field too faint for FPIA), FPIA running, no coma in initial pupils.

01:38 El 20.4 T 6.53. Converged in a couple of iterations.

01:57 El 81.75. T 5.50. Converged

02:11 El 43.5. T 5.00. Converged.

02:20 Note that the temperature has dropped 2.0 degrees in 40 minutes, so strong thermal gradients present.

02:23 Missing central hole on red and FPIA having a problem not fitting a central hole and driving in wacky aberration. Clearing C00.

02:27 El 53.5. T 4.50 , Blue only converged, trouble with spherical on DX.

02:35 Preset BS9107

02:51 EL 59.9 T=3.50, Converged.

Range-balanced pointing model data

02:55 Running pointing script. gopoint_binolbc 1 ploop+

03:08 T = 3.13

04:20 Reboot the IRTC Windows machine (for good measure)

04:25 Completion of the pointing data with 33 stars

More collimation tests at different elevations

04:38 EL 70.5, T 2.02.

04:52 cleared active optics.

05:10 El 85.1, T 2.23. Large Y values extreme delta T (3.3).

05:23 El 40.0, T 2.21, Large Y values largely went away?

05:38, EL 19.7, T 1.94

05:54, EL 54.1, T 1.57

06:05, EL 79.0, T 1.50

06:30 Hand to software group for the switchover to BP7

06:55 close for increasing winds

Early evening collimation results

Total active+ global
side and time converged x y z rx ry EL T
DX 01:34 1.107 0.238 1.877 3.035 -11.892 20.4 6.53
SX 01:34 -0.502 0.333 1.225 3.573 5.391 20.4 6.53
DX 01:57 0.970 0.825 1.419 8.867 -10.421 81.75 5.5
SX 01:57 0.120 0.941 1.227 10.114 -1.285 81.75 5.5
DX 02:11 0.290 0.001 (!!!) 1.402 0.014 -3.114 43.5 5
SX 02:11 0.319 0.823 01.325 8.842 -3.426 43.5 5
DX 02:27 no result, probably too close to moon.
SX 02:27 0.307 1.143 1.241 12.280 -3.302 53.5 4.5
DX 02:51 0.192 0.281 0.086 3.015 -2.067 59.9 3.5
SX 02:51 0.026 1.675 1.170 17.995 -0.285 59.9 3.5
  Data below taken after pointing model, more thermal gradient
DX 04:38 0.572 1.619 0.698 17.390 -6.149 70.5 2.02
SX 04:38 0.238 2.435 0.691 26.155 -2.56 70.5 2.02
DX 05:10 0.610 1.833 0.882 19.687 -6.556 85.1 2.23
SX 5:10 0.346 2.161 0.709 23.217 -3.717 85.1 2.23
DX 05:23 0.383 0.915 1.073 9.829 -4.111 40 2.21
SX 05:231 0.036 1.548 0.969 16.628 -0.389 40 2.21
DX 05:38 0.906 0.805 1.249 8.647 -9.729 20 1.94
SX 05:38 -0.376 1.140 0.848 12.242 4.043 20 1.94
DX 05:54 0.394 1.148 0.993 12.334 -4.237 54.1 1.57
SX 05:54 -0.211 1.989 1.015 21.365 2.267 54.1 1.57
DX 06:05 0.682 1.509 0.920 16.213 -7.327 79 1.5
SX 06:05 0.043 2.360 0.337 25.355 -0.462 79 1.5
|

Total collimation (Includes -0.8mm extrafocal offset)
side and time converged x y z rx ry EL T
DX 01:34 0.543 0.023 2.629 8.952 -32.184 20.4 6.53
SX 01:34 -0.887 0.129 1.972 8.268 -4.665 20.4 6.53
DX 01:57 1.160 0.771 -0.130 11.430 -0.319 81.75 5.5
SX 01:57 -0.699 0.825 -0.542 16.393 -44.306 81.75 5.5
DX 02:11 0.123 -0.238 1.480 10.261 -9.481 43.5 5
SX 02:11 -0.182 0.528 1.080 22.964 -27.056 43.5 5
DX 02:27 no result, probably too close to moon.
SX 02:27 -0.268 0.852 1.015 27.460 -32.932 53.5 4.5
DX 02:51 0.246 0.117 0.403 11.449 0.473 59.9 3.5
SX 02:51 -0.608 1.405 0.058 32.634 -33.884 59.9 3.5
  Data below taken after pointing model, more thermal gradient
DX 04:38 0.699 1.526 -0.496 22.461 -0.013 70.5 2.02
SX 04:38 -0.479 2.206 -0.958 38.829 -40.898 70.5 2.02
DX 05:10 0.803 1.854 -1.145 17.895 4.453 85.1 2.23
SX 05:10 -0.531 2.088 -1.618 26.877 -49.159 85.1 2.23
DX 05:23 0.196 0.704 1.020 18.528 -11.194 40 2.21
SX 05:23 -0.463 1.237 0.478 31.590 -23.856 40 2.21
DX 05:38 0.342 0.588 1.720 12.645 -30.249 20 1.94
SX 05:38 -0.768 0.911 1.095 18.604 -6.705 20 1.94
DX 05:54 0.383 0.986 0.444 20.365 -4.567 54.1 1.57
SX 05:54 -0.801 1.681 -0.042 37.680 -28.422 54.1 1.57
DX 06:05 0.858 1.492 -0.798 17.071 1.944 79 1.5
SX 06:05 -0.769 2.210 -1.280 33.608 -43.287 79 1.5

-- AndrewRakich - 15 Dec 2010
Topic revision: r6 - 26 Apr 2011, JohnHill
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