2016 November: Difference between revisions
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'''22:00 UT''' Began some Cyg A drift scans. Original Z offset was 200, and I could not see any increment on Cyg A, but changing to 50 gave a clear response. | '''22:00 UT''' Began some Cyg A drift scans. Original Z offset was 200, and I could not see any increment on Cyg A, but changing to 50 gave a clear response. | ||
'''22:20 UT''' Nominal peak of a drift scan (well seen on baseline 11-14) is 22:20 UT, but it actually occurred at 22:19:55 UT, so original RA offset is right: 0.15 degrees. | '''22:20 UT''' Nominal peak of a drift scan (well seen on baseline 11-14) is 22:20 UT, but it actually occurred at 22:19:55 UT, so original RA offset is right: 0.15 degrees. Also did a Dec drift scan that peaks at 22:46:00 UT, which verifies the DEC offset is also right: 1.03 degrees. | ||
'''22:49 UT''' This is the time when by focus was best, which corresponds to a focus (Z-axis) setting of 30 on the Lo receiver. Higher settings were significantly worse, so that by a Z-axis setting of 200 the amplitude is going to zero. This explains the lack of phase coherence on the 3C84 run of yesterday. | |||
Revision as of 23:01, 10 November 2016
Nov 04
19:18 UT Reboot ROACHes to clear fault light and test whether large delays are still present. They were power-cycled and reloaded.
19:24 UT Started roachcal.scd to take packet capture data for checking delays. Still bad!
Nov 05
03:41 UT Found a potential problem in DELAYCAL_END.ctl, so took another two sets of roachcal.scd data. Still bad!
04:14 UT Started roachcal.scd for another set of data. After studying schedule.py, another problem was found. DELAYCAL_END command has to have CIEL-2 as second value on the line, otherwise source id is set to None! Yay! It finally worked!
Nov 09
01:08 UT Set up the schedule to do a long run on 3C84 with the low-frequency receiver, using pcal_lo.fsq (all bands 2.5-6 GHz). One major change is that the PA can be set, so I set it for -30. I would predict that the chi-dependence will shift by 30 degrees (the phase jump will occur at a different hour angle), but the non-intersecting axes issue will cause the same symmetric phase rotation (it depends on elevation only).
04:20 UT 3C84 schedule begins.
12:00 UT 3C84 schedule ends.
Nov 10
03:00 UT Note, the above observations showed no coherence, for reasons unknown. The receiver will be checked for pointing and focus using a total power source. I attempted to observe the Moon at the current time, but it happens to be at -6 Declination, so it is in the geosynchronous satellite belt and could not be peaked up in total power. I will observe Cyg A when it rises at ~ 21:20 UT today.
22:00 UT Began some Cyg A drift scans. Original Z offset was 200, and I could not see any increment on Cyg A, but changing to 50 gave a clear response.
22:20 UT Nominal peak of a drift scan (well seen on baseline 11-14) is 22:20 UT, but it actually occurred at 22:19:55 UT, so original RA offset is right: 0.15 degrees. Also did a Dec drift scan that peaks at 22:46:00 UT, which verifies the DEC offset is also right: 1.03 degrees.
22:49 UT This is the time when by focus was best, which corresponds to a focus (Z-axis) setting of 30 on the Lo receiver. Higher settings were significantly worse, so that by a Z-axis setting of 200 the amplitude is going to zero. This explains the lack of phase coherence on the 3C84 run of yesterday.