Refine platescale by epoch

[jburkepile]

Recompute the K-Cor platescale and compare to original estimated value of 5.643 arcsec/pixel. The original estimate was made using images processed under an early version of the pipeline. The current pipeline version is much improved.

#367 is doing the 2nd task below for the entire mission.

Questions

• When the images are rescaled by a magnification factor, how should I record the old plate scale? What should I do with the various radii in the FITS file keywords and database? Should they be rescaled by this factor too?

Tasks

• Ben will send the occulters back to MLSO (always leaving one at MLSO) for the IG to remeasure the diameters
• Joan will select a number of days over the mission to remeasure the occulter diameters in K-Cor images and derive platescale value with uncertainty estimate. Use images acquired during good seeing conditions. Include images over the mission with all 4 K-Cor occulters (summer, fall-spring, old and new winter occulters).
• Have IG determine effective focal length (EFL) of Optimax 2014 objective lens and the two Optimax 2022 objective lenses.
• using the above information, and image scale plot for 2013, compute plate scale for epochs and put in epochs.cfg
• rescale images by the magnification factor determined by the nominal plate scale and epoch plate scale so that all level 1 and 2 FITS files will have the same plate scale

[mgalloy]

Dennis calculated the EFL of the K-cor Optimax lens from K-Cor zemax model, first verifying that the model included the as-built Optimax 2013 objective lens and Corning blank.

The EFL of the O1 is 2018.66 ± 0.1 mm. Need to do more thorough tolerance analysis to get better uncertainty.

Platescale at occulter: 206265/2018.66 = 102.179 arcsec / mm.

This was in Jira ticket KCOR-123.

For comparison, the Jenoptik lens has a plate scale at the occulter of 102.187 +/- 0.01 arcsec/mm.

[jburkepile]

There are 5 epochs in the KCor mission with different distortion. Here are the days to process for each distortion epoch:

epoch 1: starts 20130930

process:

• 20131015
• 20131101
• 20131210
• 20140305
• 20140723
• 20150121
• 20150603

epoch 2: starts 20150619

process:

• 20150624
• 20151008
• 20160208
• 20160610
• 20161115
• 20170214
• 20170616 (no data?)

epoch 3: starts 20170522

process:

• 20170524
• 20170901
• 20180101
• 20180519
• 20181022
• 20190301

epoch 4: starts 20190307

process:

• 20190315
• 20190501
• 20190706
• 20190924
• 20191101
• 20191212

epoch 5: starts 20191216 thru present

process:

• 20191218
• 20200612
• 20201217
• 20210319
• 20210924
• 20221111 (no data?)
• 20220731
• 20221123

[mgalloy]

I have the above data staged and have the required calibration files ready to go. Results will appear in raw.platescale on a variety of servers. See

/export/data1/Data/KCor/platescale_routing.cfg

on our standard data server for location by date. I will probably start processing tonight.

[samaiyahfarid8]

Thanks for the update. I will check the updated radii.

[mgalloy]

By the way, these days are fairly long on average, but we have slowed down quite a bit. The times taken for them:

Date	Realtime + EOD time
20131015	0:15:17
20131101	6:54:37
20131210	8:36:35
20140305	8:54:56
20140723	11:53:28
20150121	10:11:18
20150603	3:48:02
20150624	10:00:31
20151008	6:34:03
20160208	11:17:49
20160610	8:54:15
20161115	12:21:41
20170214	9:04:04
20170524	7:29:18
20170901	8:14:02
20180101	6:52:57
20180519	6:46:39
20181022	3:18:01
20190301	4:41:00
20190315	8:40:21
20190501	6:17:18
20190706	12:39:43
20190924	8:51:30
20191101	11:56:24
20191212	6:44:50
20191218	12:23:24
20200612	13:01:43
20201217	2:14:50
20210319	4:43:30
20210924	7:42:48
20220731	7:21:29
20221123	6:11:30