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