From Brent.Carlson@hia.nrc.ca Sat Apr 4 06:28:24 1998 Subject: VS05s -- PI letter To: vsog@vsop.isas.ac.jp (VSOG), bill@ras.ucalgary.ca (Bill Scott) Date: Fri, 3 Apr 1998 13:23:26 -0800 (PST) Cc: jreynolds@atnf.csiro.au (John Reynolds), trigilio@ira.noto.cnr.it, qzh@center.shao.ac.cn, kenta@vsop.isas.ac.jp, nakaji@crl.gp.jp ========================================================================== PI INFORMATION LETTER FROM PENTICTON S2 CORRELATOR FOR EXPERIMENT VS05s ========================================================================== Dear PI: This letter is to inform you of some of the details of the correlation and analysis of your experiment 'VS05s'. Your contact person at the correlator is: Brent Carlson Tel: (250) 493-2277 Fax: (250) 493-7767 email: Brent.Carlson@hia.nrc.ca and is the person who correlated your experiment. You can also contact the University of Calgary Radio Astronomy Lab for assistance with data reduction and imaging using AIPS and DIFMAP. The data package that we are sending you contains this letter and the FITS data tape in the format requested in the VS05s.sum file. Additionally, there are a number of files on the University of Calgary ftp server that will be of interest to you. The .txt file is anonymous access and all other files are restricted access only. These files include: VS05s_DQA1.txt -- ASCII *summary* file of single baseline fringe search results. VS05s.dqa1 -- ASCII file of single baseline fringe search results. VS05s_DQA1.ps.gz -- gzipped postscript file of plots of single baseline fringe search results. This includes plots of phase cal extracted at the correlator and available in your FITS data. VS05s.log -- log file generated by the correlator. VS05s.comments -- comments extracted from station log files. VS05s.tsys -- Tsys data extracted from station log files. This is not formatted to read into AIPS but is provided as auxillary information if Tsys files are not otherwise available. In addition, since this is Space VLBI data there may be times when delay discontinuities occur on space baselines (VSOP_SC) -- due to tracking station handovers and 'clock setting events' at individual tracking stations resulting from momentary loss of downlink lock. These will show up as glitches or delay jumps in the VSOP_SC phase cal data and in the fringe fits results. For convenience, all times across which fringe fitting should not be done are at the end of this file in a format ready to be read in by AIPS' INDXR. The tracking passes are as follows: 'GBANK_TS' 1997-351-16:25:00 --> 1997-351-18:36:47 'TDBIN_TS' 1997-351-22:50:00 --> 1997-352-00:35:35 ...and periods of downlink loss are as follows: 351-17:56:58.930 -> 351-18:11:01.020 351-18:36:45.030 -> 351-22:53:24.000 You will have approximately 3 weeks from today (Fri Apr 3 11:27:29 PST 1998) to look at the data and request recorrelation if there is a problem. Recorrelation requests will only be *considered* if the data is bad and it can be traced to the correlator or if there is a valid scientific reason (such as a change of correlation parameters or change of source coordinates). PLEASE LOOK AT THE DATA AS SOON AS POSSIBLE SINCE YOUR FEEDBACK TO THE MISSION IS IMPORTANT. Please contact the UofC RAL as soon as you are satisfied with the data so that re-cycling of VLBI tapes can occur with your input in a timely manner. If the data is bad or not scientifically acceptable due to problems at acquisition time, you must contact the VSOG to request re-observation of the radio source. If the data is good, then in accordance with mission policy, 18 months after it is released from the correlator, it will be available to any PI on a request basis. Good luck with your data! ================================= Correlator PR/Data analyst notes: ================================= 1. The Usuda 64m quantizer histogram is out of range for our Van Vleck/ coarse quantization correction. The ideal correction was applied and the data on all Usuda 64m baselines will be flagged as 'probably bad'. Nevertheless, the quantizer thresholds are stable and so the visibilities could be useful -- they will however, be larger than normal by about a factor of up to 1.5. Also, the autocorrelation spectrum for Usuda will show a large DC component. 2. There was one bad tape in the Greenbank tracking pass. This results in a data valid on all VSOP_SC baselines during this pass of 75% and will be flagged as 'probably ok'. This will degrade the SNR by about 17% but will not affect the visibility amplitudes. Also, during this pass, there was a fairly high tape error rate of about 2e-3 which will limit the dynamic range of the image. 3. We did not detect VSOP_SC x KA fringes, however global fringe fitting should find them. Your FITS tape(s) incl: 7 FITS files, 629948160 bytes total Participating GRTS: MOP, NOTO, SESHAN25, USUDA64, KASHIMA ================== POINTS OF CONTACT: ================== ---Correlator--- Operations email: vlbiop@hia.nrc.ca Operations Manager (Sean Dougherty): Sean.Dougherty@hia.nrc.ca Tel: (250) 493-2277 (~16:00 to 24:00 UT) Fax: (250) 493-7767 Web: http://www.drao.nrc.ca Anonymous ftp: ftp.drao.nrc.ca /pub/vsop Address: Attn: Space VLBI Dominion Radio Astrophysical Observatory Hertzberg Institute of Astrophysics National Research Council of Canada White Lake Road (P.O. Box 248) Penticton, B.C. Canada V2A 6K3 ---University of Calgary RAL--- Bill Scott: bill@ras.ucalgary.ca Russ Taylor: russ@ras.ucalgary.ca Tel: (403) 220-7424 Fax: (403) 289-3331 Web: http://www.ras.ucalgary.ca ftp: cougar.ras.ucalgary.ca public directories: /pub/vsop/ restricted directories: /usr/home/vsopobs/vsop/ (contact Bill Scott for restricted access permissions) Address: Attn: Bill Scott/Russ Taylor Physics and Astronomy Department University of Calgary 2500 University Dr. NW, Calgary, Alberta, Canada T2N 1N4 ---The VSOG (VSOP Science Operations Group)--- email: vsog@vsop.isas.ac.jp S2 Scheduler: Jim Lovell (jlovell@vsop.isas.ac.jp) Tel: +81-427-51-3934 (8am to 6pm JST) Fax: +81-427-69-8949 Web: http://www.vsop.isas.ac.jp (Web site contains schedule information, experiment status details, HALCA calibration data and data reduction info.) Address: ISAS, 3-1-1 Yoshinodai, Sagamihara Kanagawa 229, Japan ---AIPS/Data Reduction--- VSOP Data Reduction Exploder (VDR): vdr@aoc.nrao.edu -- for general help and exchange of information regarding VSOP data reduction. 'Designated AIP': daip@aoc.nrao.edu -- for reporting bugs in AIPS. ! ! Start of Formatted entries for input to AIPS' INDXR. ! These epochs are times across which fringe fitting should not be done. ! They include all tracking station handovers and clock setting events. ! SUBARRAY = 1 / 351 17:56:58.930 351 18:36:45.030 /