2020 November

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November 25

01:55 UT Start observations of 2253+161 to determine if x-axis coordinate of receiver is in the best location. This first scan is at position 510. Unfortunately, the wind is causing some back tracking, which could invalidate my tests.

02:15 UT This scan is at position 515--rather than do this by have I have created a new ctl file PHASECAL_X.ctl that allows the specification of the X coordinate on each line. Here is the schedule:

2020-11-25 01:55:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 510
2020-11-25 02:15:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 515
2020-11-25 02:35:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 520
2020-11-25 02:55:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 525
2020-11-25 03:15:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 530
2020-11-25 03:35:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 535
2020-11-25 03:55:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 505
2020-11-25 04:15:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 500
2020-11-25 04:35:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 495
2020-11-25 04:55:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 490
2020-11-25 05:15:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 485
2020-11-25 05:35:00 PHASECAL_X 2253+161 pcal_hi-all.fsq 480
2020-11-25 05:55:00 PHASECAL+X 2253+161 pcal_hi-all.fsq 510
2020-11-25 06:15:00 STOW

13:41 UT The above ran fine, and I can see a steady decline in the quality of the phase coherence as the offsets change. The best phase coherence is clearly at 515 mm, which is 5 mm off from the nominal position. However, since a pointing offset can do the same thing, I think we are okay to leave it at its nominal position and do a pointing calibration. This takes around 24 h to complete, so I will start it this evening after the last calibration of the day and let it run through Thanksgiving. If the wind cooperates, we should have an update in time to continue observations on Friday, Nov. 27.