Summary of the GMVA Session, May 4-9, 2023 Vers. 4; TPK 31-05-2023 ******************************************* Stations participating: Eb, On, Mh, Ys, Nn VLBA(8) @3mm, VLBA(10) @7mm 2xKVN (no KVN_TN) other: ALMA GLT GBT LMT (part time) Haystack (part time for test) JCMT (only MP005A&B) MOPRA ATCA =========================================================== European Fringetest: -------------------- f231a - Fringes found to Eb, On, Mh, Ys, (+Nn at the beginning of c231a) =========================================================== Notes from individual stations: Effelsberg: ----------- The weather was mixed, degrading from the beginning to end. Lots of clouds and some hours of rain. Some interruption due to lightening warning. May 4: 12 UT Ef is ready as well. Weather is good, clear sky and sunny. Pointing on BL Lac looks good. 16:30 UT EB started c231a on time, clear sky, Tsys~180 K May 5: 12:20 UT EB continues observing, now its getting more cloudy, Tsys=210 K, 20mm water, but still can point on BLLac. 17:40 UT We started c231b a bit late, due to a thunderstorm warning, now we point on 3C273, Tsys=220 K @ elv=20deg, cloudy conditions, 15mm pwv. May 6: 08 UT Last night went smoothly, now we move to the NGC1052 project. Tsys 250K at elv=35deg. Forecast for the day is mixed cloud and sun with possibility of rain showers in the afternoon. 14:40 UT EB is now affected by rain, we point at 27 GHz and do VLBI at 86 GHz, though with marginal performance, Tsys ~300 K 19:30 UT rain is over, but cloudy. Pointing and focus done on 3C273, Tsys=195K at elv=65 deg, pvw=20mm. 22:00 UT EB started c231c on time May 7: 10:45 UT Effelsberg had good weather last night, but now the cloud coverage increases, Tsys ~220K. Technically everything looks ok. 19:40 UT After heavy rain in the afternoon, EB has resumed observation at 17 UT, but we are still under clouds. May 8: 04:00 UT Last night EB had bad weather, heavy rain and thick clouds, Since 3 UT is getting better and we are now pointed on 0954+65 and observing. Tsys=250K at elv=20. 18:30 UT Effelsberg is now observing the last project in this session, which is MP005B (M87). It is cloudy but the clouds are not very thick and we can point on 3C273 quite well. Tsys~220 K at 40 deg, 23mm H20. No more rain predicted. c231a - start under good weather conitions c231a No053-059 missed No076-088 bad weather c231b No001-003 missed No023-024 missed No096-127 rain c231c No074-086 missed, bad weather c231d ok, cloudy Onsala: ------- May 4: good weather May 6: no known problems, weather is very good, partly cloudy, lots of sun during daytime. from Jun Yang: Onsala station successfully participated in the NME F231A and all the science experiments (C231A-D )of the GMVA session 1/2023 with its DBBC2 backend. The weather was incredibly wonderful through the entire session. Thanks to the blue sky and light clouds, the opacity-corrected Tsys* were <200 K for most time of the observations. The pointing model was updated just before the session. If works fully as expected, the remaining pointing errors would be very small, 1 sigma=3 arcsec in both AZ and EL. All the data were recorded on the default astro-VLBI Flexbuff Bogar. There are dedicated account (bonn) and JIVE5ab for the correlator group to fetch the data at any time. The FS log files and the antabfs files have been automatically uploaded to the ftp server VLBEER. Moreover, we have got our 2L2H DBBC3 backend to run the experiments F231A and C231 B-D with a data rate of 16 Gbps in parallel. During F231A, the input signal were not correct. Thus, its data could be removed and the experiment C231A was skipped. In the later experiment C231 B-D, we fixed the issue. These data could be used to search for fringes. During the first 1-3 seconds of scans, there might be a certain packet loss. Because the backend did not control the hot load, there were no Tsys data available in the FS log file. The VDIF data were recorded on the new Flexbuff Koll. If there are reasonable good fringes from the backend, one may use the antabfs files of the DBBC2 backend to calibrate the data. Metsahovi: ---------- May 4: scattered clouds May 6: 19:30 UT Clear skies, Tsys ~180K. Next two days look good weatherwise! Yebes: ------- Here is the report from Yebes for GMVA May 2023 session. Bad weather affected the whole session. Attached are the antabfs plots with Tsys over 150K for most of the time. Unfortunately, although the W-band pointing model was checked and updated before the session, it was later found that its performance was not as good as expected. Bad weather also prevented proper pointing and focus correction for several of the scheduled gaps. For each observation: f231a: all sources tracked, fringes demonstration in real-time successful. Recorded 2003.4GB versus 2304GB planned (recording factor 0.87). c231a: lost scan no0126 after pointing/focus adjustment. Recorded 19040.1GB versus 21442.6GB planned (recording factor 0.89). c231b: antenna late for more than 10sec for 2 scans (no0067, no0182). Recorded 24719.6GB versus 27985.9GB planned (recording factor 0.88). c231c: lost 3 scans (no0103, no0159, no0161) after pointing/focus adjustment. Recorded 25082GB versus 28477.4GB planned (recording factor 0.88). c231d: lost scan no0043 after pointing/focus adjustment. Recorded 17952.6GB versus 20459.5GB planned (recording factor 0.88). NOEMA: -------- May 4: not observing (planned) May 5: NN joins c231a at 12 UT, pha_eff~0.9 16:30 UT weather degrading, pha_eff~0.5 May 6: NOEMA is entering the break between 07:22 and 16:00 UT. In c231b, we lost polarization RCP between 02:00 and 04:00 and four scans between 03:02 and 03:25. 16 UT: rain 17:45 UT: continue c231b until end May 7: NOEMA started c231c on time, conditions generally good but with some cloudy passages 3 UT: Preliminary NOEMA flux estimates: NGC3998=76 mJy, NGC5077=51 mJy, NGC4594=151 mJy for 3C279=10.45 Jy 4 UT: NOEMA enters a gap in our part of the schedule. Forecast for next evening is not good (our gap should end at 18:00 UT), but weather should improve in the second half of the night. 19:20 UT: resume observations on time after the gap. Occasional foggy passages, phases stable. KVN: ----- c231a: KVNYS Only scans 5-11 were recorded due to the rain. UT 125 12:30 - 15:24 rain & very high Tsys. KVNUS Only scans 5-11 were recorded due to the rain. UT 125 12:30 - 15:24 rain & very high Tsys. c231b: KVNYS Abort after scan 33 due to the rain. Late start by ~1 hour for MP005A observation due to the rain. Tsys was high. KVNUS Late start for MB005A observation due to the rain. Tsys was high. Late start for MP005A observation due to the rain. Tsys was high. Tsys was high for MI004 and MB019C observations. c231c: KVNYS Rain & high Tsys for POLCAL4 & MP008 KVNUS Rain & high Tsys for POLCAL4 & MP008 c231d: KVNYS The vex file was manually updated between Scan 47 and 48. Late start for MR014B by a few minutes for pointing and focus calibration. KVNUS The vex file was manually updated between Scan 47 and 48. Late start for MR014B by a few minutes for pointing and focus calibration. Cross-scan calibration information could not be automatically updated. ATCA: ----- from Phil Edwards: Tsys and weather information is here: https://www.atnf.csiro.au/vlbi/dokuwiki/doku.php/lbaops/lbamay2023/start LMT: ----- May 5: start on time, tau ~ 0.15 stop observing after scan 598 May 6: join c231b, Tsys~94K, tau~0.1 13h30 UT: LMT has finished the observations for c231b. We missed scan 885 and were slightly late on some scans. Otherwise everything ran smoothly. May 7: 01:00 UT LMT is ready to start c231c, tau_225GHz ~ 0.26 & Tsys~105 K 11:50 UT LMT will stop observations after scan 670. May 9: 0 UT: We have very bad weather now at the LMT (snow and nearby thunderstorms) and the forecast for the rest of the night is not promising, so we wont be able to join the array. GLT: ----- May 5: start c231a on time, Tsys ~ 200K, tau~0.2 JCMT: ------ May 6: 3 UT - trouble shooting, ptg ok but problems to measure Tsys May 9: 3:30 UT - We are on source on time from the start. Tau is getting lower and current tau225 ~ 0.2. Haystack: --------- from Jens Kauffmann: We only attempted to observe for a few hours, as we are still in an engineering mode. That said, those observations were very successful. For experiment c321b we observed from 2023-126-03:00 to 2023-126-04:30. (We started earlier, but dealt with a warm receiver earlier in the day.) We were hitting most scans and took data for M87, 3C279, and 3C273. For experiment c231c we observed from 2023-127-12:30 to 2023-127-15:30. We were hitting all scans and took data for 3C84 and NRAO150. GBT: ------ C231A - from Pedro Salas: The GBT could start observing at 00:00 UT. The pointing drifted by <6" during the observation. The aperture efficiency was estimated to be 0.16 (surface rms 340 microns). More details here: https://safe.nrao.edu/wiki/bin/view/GB/Observing/WbandVLBACal/MP005A Brenne Gregory was the GBT science support for GMVA runs C231B and C231C: These runs went well only running into a couple of small issues software wise with some needed system restarts (~30 mins during C231C). The weather was not ideal and resulted in having to drop down to X-band to maintain good pointing solutions. C231B - the weather was relatively clear throughout the night with little wind. C231C - The first couple of hours had good weather with low winds and few clouds. As the day progressed there was rain, overcast skies, and wind gusts up to 5 m/s. The rain subsided around 23:00 UTC. The beginning of the project was slightly delayed and we started recording about 12:00 UTC as the active surface had to be restarted (130 disabled actuators at the beginning of the project). ALMA: ------ e-Mail from Hugo Messias: We've been rather lucky within the whole bad weather front that ALMA got hit with. So far, we had a few windows where we had to stop due to strong winds and at the start of the observations the data quality hasn't been ideal due to high phase instability. More details later. VLBA: ------ general: no BR all: Tsys measurements in LCP get a 999.00 after 7mm pointing scans, issue cannot be fixed easily. This is caused by the 2nd RDBE, which is not used during preceeding pointing scans, and does not come back quick enough for subsequent VLBI scans. ------------------------------------------------------------------------------------ Project: C231A Observer: Krichbaum, T. Project type: GMVA Obs filename: c231a.vex Date/Day: 2023MAY04/124 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator: Alan Kerr 1600 Begin at EF (and other non-VLBA sites) 2253 Begin at NL 2313 Begin at FD,LA,PT,KP,OV,BR 2313-0003 *BR 7mm dead. WO-17253 FE 50 25 2335-2347 *BR out for Site Tech to work on antenna. HWA 100 12 0000 Date is 2023MAY05/125. 0003-1520 *BR 7mm and HVAC problems continue. Antenna HWA 100 917 removed from observation. 0213 Begin at MK 0555 New operator: Jessica King 1338 New Operator: Paul Padilla 1520 End at VLBA sites. 1524 End. Downtime Summary: Total downtime : 954 min Percentage downtime of observing: 8.5% Average downtime per hour : 5.1 min Total scheduled observing time (# Antennas): 11232 min (8) -------------------------------------- Project: C231B Observer: Krichbaum, T. Project type: GMVA Obs filename: c231b.vex Date/Day: 2023MAY05/125 Ants Scheduled: SC HN NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Paul Padilla 1538 Start at VLBA sites except SC,HN 1538-2355 *BR out, 7mm and Vertex HVAC are bad VAC 100 1937 1614-1620 *NL FRM Rotation Drive Fault FRM 100 6 1806-1947 *MK out for scheduled USNO observation SCH 100 101 1936-1938 *LA autostowed, wind gust? WEA 100 2 2024-2027 *LA autostowed WEA 100 3 2140 New operator: Alan Kerr 2149 Begin at GB 0000 Date is 2023MAY06/126. 0011 %NL raining. 0030 %LA raining 0600 New operator: Jessica King 0721-0833 *MK out for USNO observation. SCH 100 72 1122 End at GB 1353 New operator is Betty Ragan 1400 Begin at HN, SC 1915 %FD windy. 1955 %PT windy 2207-2221 *NL stowed for site tech to work on vertex VAC 100 14 room HVAC (WO-17266) 2339-2354 *NL stowed for HVAC again. (WO-17266) VAC 100 15 2355 End. Downtime Summary: Total downtime : 2150 min Percentage downtime of observing: 11.1% Average downtime per hour : 6.7 min Total scheduled observing time (# Antennas): 19370 min (10) -------------------------------------- Project: C231C Observer: Krichbaum, T. Project type: OTHER Obs filename: c231c.vex Date/Day: 2023MAY07/127 Ants Scheduled: NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Betty Ragan 0008 Begin at VLBA sites. 0008-1028 *BR out due to HVAC problems. (WO-17253) VAC 100 2060 0145 New Operator: Victor Acosta 0721-0832 *MK out for scheduled USNO observation. SCH 100 71 1119 Begin at GB 1345 New operator is Betty Ragan 1807-1952 *MK out for scheduled USNO observation. SCH 100 105 2205-2338 *NL parked. Site tech reports very bad lightning WEA 100 93 storms in the area and recommends stowing the antenna. 2215 %LA windy 0000 Date is 2023MAY08/128. 0145 New Operator: Victor Acosta 0752 End at GB. 1028 End. Downtime Summary: Total downtime : 2329 min Percentage downtime of observing: 14.1% Average downtime per hour : 8.5 min Total scheduled observing time (# Antennas): 16480 min (8) -------------------------------------- Project: C231D Observer: Krichbaum, T. Project type: GMVA Obs filename: c231d.vex Date/Day: 2023MAY08/128 Ants Scheduled: NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator: Victor Acosta 1030 Begin at all VLBA site except MK 1030-1053 *BR out due to HVAC problem. (WO-17192) VAC 100 1463 1030-1529 *KP executor will not restart. SW 100 299 1030 %NL tsys high. Weather has been bad, with recent storms 1147 Begin at MK 1345 New operator is Betty Ragan 1456 KP parked, since it's not getting any data. 1859-1915 *LA put in standby briefly for site techs to OTHER 100 16 do some work. 2138 New Operator: Paul Padilla 2149 GB joins 0000 Date is 2023MAY09/129. 0233 End at EF. 0400 %LA raining 0545 New operator: Alan Kerr 0753 End at GB. 0913 End at NL. 0953 End at FD. 1013 End at LA,PT,KP. 1053 End at OV,BR. 1333 End at MK. 1553 End. Downtime Summary: Total downtime : 1778 min Percentage downtime of observing: 12.6% Average downtime per hour : 7.6 min Total scheduled observing time (# Antennas): 14104 min (8) Notes: * = Entries where data was affected. % = Entries where data may have been affected. & = Entries where the site tech was called out. WEA = Weather entries. MF# = Maintenance form or major downtime category associated with a problem. %AD = The percentage of an antenna affected by a problem. AMD = Total antenna-minutes downtime for a problem. Tsys = System Temperature (TP/SP x Tcal/2) ACU = Antenna Control Unit FRM = Focus/Rotation Mount RFI = Radio Frequency Interference CB = Circuit Breaker