Summary of the GMVA Session, April 23 - 28, 2020 ================================================ Stations participating: Europe: Ef, On, Mh, Ys US: 8xVLBA KVN: yes, after observation data storage server broken, all data lost (Scheduled but not participating due to Corona shutdown: ALMA, GBT, Pico Veleta) ============================================================================================================ European Fringetest: f201a: fringes found to: On, Mh, Ys, no fringes to Ef f201b: fringes now also found to Ef (Ef had a 2 MHz LO offset in the 3mm receiver, which was fixed before c201a) Apr 23: F201A Ef: clear sky, Tsys ~ 190 K On: nice weatheri, opacity corrected Tsys* ~ 150K Ys: partly cloudy Tsys ~ 160K Mh: V-shape in bandpass seen after fringe test, revert back to older dbbc2 firmware Apr. 24: F201B Onsala is using DBBC2#2 with the firmware DDC V107 Beta 3, Tsys* ~ 180K Mh: joined, V-shape has dissappeared Ys: not available Ef: joined, try parallel recording with DBBC and RDBE detected 2 MHz LO offset, now found fringes (SNR 245 on Ef-On, SNR 15 on Ef MH) ============================================================================================================ Science part: C201a, Apr 24 Ef: started on time, some clouds, Tsys ~ 200K On: started on time, light clouds, Tsys* ~200K Mh: started on time Ys: started on time, lost opacity records in the logfile, calibration method changed to single load Apr 25 Ef: some clouds, Tsys ~ 200K On: blue sky Ys: rainstorm from 6:30 to 7:45 pm C201b Apr 26 Mh: started on time Ef: started on time, blue sky, later found that automatic gain control (DBBC, agc) is bad for LCP, fixed after 6 UT Ys: started on time C201c Apr 26 Ys: started on time Mh: started on time Ef: started 15min lates, pointing issues C201d Apr 27 Ef: started on time, clear sky and cold (T=3 C), Tsys 180 K, clouds during daytime Mh: started on time, clear sky On: raining C201e Apr 27 Ef: started on time, partly cloudy Mh: started on time, cloudy Ys: started on time, partly cloudy, after 9:41pm rain =============================================================================================================== Station Details Effelsberg: observing under quite good conditions, mostly clear sky. During day time sun-heating and atmospheric turbulence affect pointing, and led to the loss of some data (in particular for 1803+78). Problem with Dual Pol, most likely only single Pol until c201c, after c201d dual pol fixed. c201a Apr 24: 19h30 scan lost Apr 25: 03h15 scan lost 06h15 problems telescope control 20h45,21h00 scans lost, pointing problems c201b Apr 26: 02h20 perhaps bad, telescope control problems, after 5h20, cannot point on source 07h40, 08h00 no VLBI, try to fix pointing 09h00 back on source 11h20 lost c201c Apr26/27: 13h00 not observed 17h15 lost 17h30 lost c201d Apr 27: 06h00 lost 08h15 lost after 08h30 until 15h30, pointing uncertain, can't see source, too much sun 15h45 to end: recover poiting, should be ok c201e Apr 27: good weather, no scans lost Yebes: observing remotely because of Corona restrictions c201a: Halted at 16:38 UT due to a severe hail storm Resumed at 17:59 UT. 116/121 scans recorded, total of 25/27 TB. Scans lost: 787, 793, 799, 805, 811. c201b: 74/74 scans recorded, total of 12.33/12.51 TB. c201c: Light clouds during all the scheduled time. 48/48 scans recorded, total of 10.48/10.81 TB. c201d: The observation was halted at 08:06 UT to check pointing. Pointing checkout towards Venus at low elevation (13o) successful, no corrections needed. Resumed observation at 08:31 UT. Some thick clouds. 55/56 scans recorded, total of 11.87/12.28 TB. Scan no0102 not recorded because of pointing checkout. c201e: Cloudy, with rain between 18:00 and 20:30 UT. 64/64 scans recorded, total of 9.46/9.61 TB. Metsahovi: - c201a: No known problems. Clear sky. - c201b: No known problems. Clear sky. - c201c: No known problems. Partly cloudy. - c201d: No known problems. Clear sky. - c201e: No known problems. Cloudy. KVN: observed, but data storage server broken, all data lost. ============================================================ VLBA Logs VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C201A Observer: Krichbaum, T. Project type: VLBA Obs filename: c201a.vex Date/Day: 2020APR24/115 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Betty Ragan. 2054 Begin at OV,BR,MK 2058 Begin at other sites. 2124-2129 *PT autostowed. Power glitch. COM 100 5 2137 New Operator: Paul Padilla 2228-2241 *PT autostowed, power glitch? COM 100 13 0000 Date is 2020APR25/116. 0545 New operator is Alan Kerr 0651-0838 *PT,MK out for daily USNO observation. SCH 200 214 1350 New operator: Jessica King 1830-1833 *KP autostowed, power glitch? Repointed. COM 100 3 2152-2154 *KP autostowed, power glitch? COM 100 2 2220 %BR high winds. 0000 Date is 2020APR26/117. 0049 %OV high winds. 0150 New operator is Carolyn Morris 0359 End. Downtime Summary: Total downtime : 237 min Percentage downtime of observing: 1.6% Average downtime per hour : 1.0 min Total scheduled observing time (# Antennas): 14920 min (8) VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C201B Observer: Krichbaum, T. Project type: VLBA Obs filename: c201b.vex Date/Day: 2020APR26/117 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator: Carolyn Morris 0454 Begin (except MK) 0511 Begin at MK 0726-0902 *PT,MK out for daily USNO SCH 200 192 1336-1337 *KP autostow COM 100 1 1350 New operator: Jessica King 1351-1357 *MK autostowed, power glitch? Repointed. COM 100 6 1833-1839 *NL DBE2 dropped out. Record rate is half. WO-5610 REC 100 6 1856-1902 *NL DBE2 dropped out. REC 100 6 1930 End. Downtime Summary: Total downtime : 211 min Percentage downtime of observing: 3.0% Average downtime per hour : 1.8 min Total scheduled observing time (# Antennas): 7008 min (8) VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C201C Observer: Krichbaum, T. Project type: VLBI Obs filename: c201c.vex Date/Day: 2020APR26/117 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator: Jessica King 1953 Begin, all but OV,BR,MK. 1953-0650 *NL DBE2 occasionally drops out. Record rate will be REC 5 32 half during these times. WO-5610 1954 BR begin. 1956 OV begin. 2308 MK begin. 0000 Date is 2020APR27/118. 0150 New operator is Carolyn Morris 0650 End. Downtime Summary: Total downtime : 32 min Percentage downtime of observing: 0.6% Average downtime per hour : 0.4 min Total scheduled observing time (# Antennas): 5256 min (8) VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C201D Observer: Krichbaum, T. Project type: VLBA Obs filename: c201d.vex Date/Day: 2020APR27/118 Ants Scheduled: NL FD LA PT KP OV BR MK =UT-Time===Comment===============================================MF#===%AD==AMD= Operator: Carolyn Morris 0653 Begin 0653-0832 *PT,MK out for daily USNO SCH 200 198 0832-0842 *PT,MK zero record rate REC 200 20 1350 New operator: Jessica King 1422-1423 *PT RSPR was restarted. SW 100 1 1522-1524 *KP autostowed, power glitch. Repointed. COM 100 2 1637 MK end. 1656 End. Downtime Summary: Total downtime : 221 min Percentage downtime of observing: 4.6% Average downtime per hour : 2.7 min Total scheduled observing time (# Antennas): 4824 min (8) VERY LONG BASELINE ARRAY OBSERVING LOG -------------------------------------- Project: C201E Observer: Krichbaum, T. Project type: VLBA Obs filename: c201e.vex Date/Day: 2020APR28/119 Ants Scheduled: NL FD LA PT KP OV BR MK GB =UT-Time===Comment===============================================MF#===%AD==AMD= Operator is Betty Ragan. 0033 Begin. 0030 Begin at all sites except GB,MK. 0050 Begin at GB. 0050-0859 *GB not running, due to lack of 3mm reciever. FE 100 489 0254 Begin at MK. 0533 New Operator: Paul Padilla 0851-0859 *PT,MK out for daily USNO observation SCH 200 16 0859 End. Downtime Summary: Total downtime : 505 min Percentage downtime of observing: 12.5% Average downtime per hour : 7.5 min Total scheduled observing time (# Antennas): 4048 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 VME = Site control computer CB = Circuit Breaker vclock = Program that compares site clock time to a standard.