2017 August
Aug 10
02:10 UT After many days of the system running normally, we had a glitch today that I did not notice until this evening. The ROACH clock was messed up...so we took a lot of very short files since 16:03 UT on Aug. 09. Luckily, I was able to get the clock working again, and I should be able to bring the system up and reset delays, etc.
02:17 UT Well, we are on 3C273 and tracking, so it was a fast recovery. I will take data for 20 min or so and set the delays. 3C273 will set soon, but I should be able to check delays on 3C286, at least to see if they are rational. One thing I will need to check is whether the X-Y delays change as a result of rebooting the ROACHes. I will set up to observe 2253+161 and do an X-Y delay calibration.
02:58 UT Not bad! I got the delays reset from the 3C273 observation, and will take my X-Y delay measurements starting at 08:25 UT, both with low and high receivers. However, I have not set the low-receiver delays. Ant 14 may be off by 2 ns as a result (it was on the high receiver).
Aug 11
02:58 UT I updated the delays slightly for both lo and hi receivers (differed only by 2 ns on Ant 14, since none of the others should change). This was after the day's observations, so yesterday's observations (i.e. Aug. 10) can be calibrated with the refcals taken up to now, while today's (i.e Aug. 11) observations will require the new refcals from later this UT day.
Aug 29
10:30 UT The correlators were rebooted in attempt to fix the glitches in the dynamic spectrum (see any plot from 08/28). Delays were updated (ant8 needed the second iteration).