User Tools

Site Tools


lbaops:lbamar2011:vt13egmlog

Good data from 04:46 UT onwards

failure of the main communication links from the control computer to the antennas, and no commands are going to the antennas. This happened at ~ 06:30 UT, just about the time the cycle on the two sources J2225-0457 & J2218-0335 came to an end, and the one on J2348-1631 & J2354-1513 was to begin


                 Observing Log for VLBI test of 8 Mar 2011
                 ------------------------------------------

Participating telescopes : GMRT + ATCA + Mopra

Configuration at start of expt : RF band = 1390, LO-I = 1330, LO-IV = 60, LO-V = 140 (& 165), IF BW = 16

Test on 3c468.1 : fringes seen on all working antennas ; weak fringes on C03.

Antennas selected for VLBI experiment : C00, C01, C02, C04, C05, C06, C08

(note : C04, C05, C06, C08 connected to BB monitor port o/p (both pols)

0x:xx : Fringes still seen on ALL working antennas in GSB, except C08 !! no LTA file recorded !!

Slew to source 2253+1608 : need to go from outer to inner =⇒ 10 mins delay !! Fringes seen in GSB.

Meanwhile, checked disk mounting and remounted the data recording disks.

Stopped real-time mode of GSB : hltndas.gsb

Started raw-dump mode and did a short test : 09:57:00 onwards, for 100 blks

Ready to start actual run : already about 30 mins behind the schedule ! =⇒ edited the cmd file accordingly to drop some of the initial pointings

Sources to be done today are (all are being taken from main GMRT source list) :

J2253+1608 (named 2253+161 in the GMRT source list) 10 Jy @ 20 cm; UVMax 7 kL

J2218-0335 (named 2218-035 in the GMRT source list) 1.0 Jy @ 20 cm; no UVlimits

J2225-0457 (named 2225-049 in the GMRT source list) 5.7 Jy @ 20 cm; UVMax 45 kL

J2348-1631 (named 2348-165 in the GMRT source list) 2.7 Jy @ 20 cm; UVMax 15 kL

J2354-1513 (named 2354-152 in the GMRT source list) 1.0 Jy @ 20 cm; UVMax 30 kL

changed # of blocks in run_rawdump.csh of readSHM to 7200 (for 30 mins).

Recording #1 :

start at :  2011 03 08 09 59 00 ;  stopped at : 10 24 00
raw_voltage1.vlbi_8mar_1.node0.scan0 

should have been on 2253+1608 since the beginning, but had problems with 
the cmd file and had to fix things (cmode 0 vs cmode 1 -- latter needed
for fixed time command execution !!)
finally, useful data on 2253+1608 is only from 10:12 or so onwards !
 
first change of source in sync with schedule is at 10:16:00 to J2225-0457
after that things are in sync...
typical settling time for the antennas to be on source is 30 sec ==> good
data can be said to be available from 30 sec from nominal start minute,
for each scan.
killed at 10 24 00, at end of scan on J2218-0335

Recording #2 :

start at :  2011 03 08 10 25 00 ;  stopped at : 10 53 30
raw_voltage1.vlbi_8mar_2.node0.scan0 
reached on source (J2253+1608) at 10:27:00 but immediately had problems 
due to changes made in cmd file !! 
fixed and restarted cmd file ; back on source (J2253+1608) at 10:29:30 
==> 4.5 mins of good data till change of source to J2218-0335
killed at 10:53:30  (while on J2218-0335 scan)

Recording #3 :

start at :  2011 03 08 10 54 00 ;  stopped at : 11 24 00
raw_voltage1.vlbi_8mar_3.node0.scan0 
first source is J2225-0457 (usual 30 secs safe time from min value)
last source is J2253+1608 (stop is in the middle of this scan)

Recording #4 :

start at :  2011 03 08 11 28 00 ;  stopped at : 11 58 10
raw_voltage1.vlbi_8mar_4.node0.scan0 
first source is J2218-0335 (on src is 50 secs after start!)
last source is J2225-0457 (stop is in the middle of this scan!)

Recording #5 :

start at :  2011 03 08 12 00 00 ;  stopped at : 12 31 10
raw_voltage1.vlbi_8mar_5.node0.scan0 
first source is J2218-0335 (on src is 30 secs after start)
at around 12:05, commh system failed ==> no commands going from 
online to antennas !!
last source is ..... 
observation aborted;  took about 1 hour of debugging for the problem to be 
  identified and fixed.  Resumed observations from 13:14 onwards.

Recording #6 :

start at :  2011 03 08 13 14 00 ;  stopped at : 13 30 30
raw_voltage1.vlbi_8mar_6.node0.scan0 
first source is J2354-1513 (already on src at start!)
last source is J2348-1631 (stop afer end of the scan)

Observing run over !!

lbaops/lbamar2011/vt13egmlog.txt · Last modified: 2015/12/18 16:38 (external edit)