Using vsop_n.pro profile.
Reference antenna is CA01 on W104.
Using new “hybrid” CABB mode (cfb64_1m-64m_vlbi) with 2048x1MHz channels in IF1 and 64MHz channel for tied array in IF2. So, IF1 will have internal ATCA baseline data, including Tsys measurements. Observers = Jamie S and Phil E.
Started experiment with all 5 track antennas in the tied array. Changed this to only CA01 at 01:05:37 due to increasingly poor seeing phase rms.
Rephased array at 02:52, although leaving the tied array with only CA01.
07:00 UT: Seeing monitor has dropped below 500microns – will add antennas back into the tied array during slew to next strong source, 1718-649 at 07:40UT
07:30 do pcal after 30 secs of 2005-489 scan to check phase up and stability. Looks okay.
07:40 UT: tie ant 12345 12345 tie gain 0.1 0.1 t=26 C, P=991 hPa, Rel. humidity = 45%, wet path = 130mm
08:47 another pcal, and again at 08:49, on 1718-649 scan.
11:45 UT 1934-638 scan. we had amplitude calibrated at the start using the “acal 0 0” option, however, on 3C279 at relatively low elevation in relatively poor weather. On the current 1934 scan, assistance reports F1 = 0.290 x 0.824 (where the latter is the expected f.d. of 1934-638 at these freqs) and F2 = 0.120 x 0.824. So nominal Tsys values for ATCA baselines in IF 1 are correspondingly in error (but can be fixed).
11:49 Phases varying quite a bit during this scan, and seemon spiking to 770 microns. (Current elevation ~30 degrees). Wind suddenly picked up at same time. After ~10 mins phases steady down again
12:20 phase up (the 5 ants in tied array) on 2052-474.
1245: seemon peaks up around 1700microns and phase stability poor
13:13 phase up on 0405-385 and seemon improving
22:03 UT phase up on 1144-379. Seemon has been about 250 microns for the last ~5 hours. Phase up again at 22:08. The baselines between CA01,2 &3 (which are close together) stay pretty good, but those to CA04 & 5 (which are close to each other) wander by +/-60degrees. May take out CA04 and CA05 shortly as the day warms up and seemon increases.
00:30 tie ant 123 123 Phase excursions on baselines to ca04 and 5 are getting larger, so drop back to 3 ants.
00:51 I hadn't changed gain when re-tieing the array as the DAS was happy, but it's started complaining, so tie gain 0.2 0.2
03:05UT: 1121-640 scans show ATCA amplitudes well down on baselines to ca06, but significant wrap in phase with freq across band (> 1 turn over the 2 GHz ATCA bandwidth) and non-zero phases. Is this a source position issue?
Yes! The schedule file has 11:23:18.8, -64:17:49.0 as the position, but the Petrov VLBI catalog gives 11:23:19.414677, -64:17:36.19545.
03:12UT: 1343-601 is a nice bright source, so do a pcal.