From analysts@aoc.nrao.edu Thu Oct 26 10:46:37 2000 Date: Wed, 25 Oct 2000 16:57:34 -0600 (MDT) From: Data Analysts To: jive@jive.nl, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, reynolds@jive.nl, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbi@oso.chalmers.se, vlbifriend@bootes.hartrao.ac.za Subject: ES036 PI Letter Dear PI, We have examined the data for project ES036 on 22 Sep. 2000. The contact person for this project was Data Analyst. Here's a summary: 1. Tape weights vs. time plots have been generated for the entire time range of your experiment. These are a measure of tape record/playback quality, representing the fraction of valid data samples. Data with weights below 70-75% should be flagged. However, you may want to be more cautious when dealing with non-VLBA stations. The easiest way to estimate the best weight threshold is by looking at the tape weights vs. time plots generated here. You can find the weights plots at /home/aspen6/astronomy/sep00/es036/sniffer/final/wtsfile.ps. If your experiment involves more than one distribution tape then there will be a tape# subdirectory between /final and wtsfile.ps. See /home/aspen6/README.sniffer for instructions on how to interpret this plot. 2. Delay, rate, phase, and amplitude plots were made for the observation. 3. Autocorrelation bandpass plots were generated for all antennas for scans on all sources. 4. Cross-correlation bandpass plots were generated for all baselines to EB for scans on all sources. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/aspen6/astronomy/sep00/es036. 6. The jobs associated with the correlation of ES036 can be found at: /home/aspen6/astronomy/sep00/es036/jobs. These files provided the correlator with all ancillary data needed for VLBI, including: correlation parameters and telescopes correlated in the final production. The job numbers are: 4420-4429 7. Operations staff have devised a web browser to navigate the file server aspen, as well as view and retrieve its text and PostScript files, gzipped or not. This browser can be reached through the VLBA homepage http://www.aoc.nrao.edu/vlba/html/VLBA.hmtl, initially under What's New but eventually under Observing. All of the files mentioned above can be accessed either with this browser or by FTPing to the vlbiobs account on aspen. NOTES: EB: IF channel 2 exhibits low sensitivity in the apd plots (50% of IF channel 1). Polarization channels were exchanged. This was corrected for the correlation. HH: Slightly variable weights. JB: Variable weights at 15:45 - 16:10 UT; weights are around 80%. Tape problem. NT: Recorder problems at site. No data. ON: Small RFI spikes seen in both IF channels in the autocorrelation plots. TR: Polarization channels were exchanged. This was corrected for the correlation. Severe RFI seen in IF channel 1 (LCP) in the autocorrelation plots. From analysts@aoc.nrao.edu Tue Oct 31 10:09:24 2000 Date: Mon, 30 Oct 2000 11:45:31 -0700 (MST) From: Data Analysts To: jive@jive.nl, kb@astro.uni.torun.pl, lorant@stad.dsl.nl, p062gra@mpifr-bonn.mpg.de, vlbi@jb.man.ac.uk, vlbi@oso.chalmers.se, vlbifriend@ira.noto.cnr.it Cc: lfoley@zia.aoc.NRAO.EDU Subject: EP038 piletter Dear PI, We have examined the data for project EP038 on 19 Sep. 2000. The contact person for this project was Data Analysts. Here's a summary: 1. Tape weights vs. time plots have been generated for the entire time range of your experiment. These are a measure of tape record/playback quality, representing the fraction of valid data samples. Data with weights below 70-75% should be flagged. However, you may want to be more cautious when dealing with non-VLBA stations. The easiest way to estimate the best weight threshold is by looking at the tape weights vs. time plots generated here. You can find the weights plots at /home/aspen6/astronomy/sep00/ep038/sniffer/final/wtsfile.ps. If your experiment involves more than one distribution tape then there will be a tape# subdirectory between /final and wtsfile.ps. See /home/aspen6/README.sniffer for instructions on how to interpret this plot. 2. Delay, rate, phase, and amplitude plots were made for the observation. 3. Autocorrelation bandpass plots were generated for all antennas for scans on NGC7538(line), W3(OH)(line), J0228+6721(cont), J2322+5057(cont), J2038+5119(cont), J1847+0810(cont), J1922+1530(cont).. 4. Cross-correlation bandpass plots were generated for all baselines to EB for scans on NGC7538(line), W3(OH)(line), J0228+6721(cont), J2322+5057(cont), J2038+5119(cont), J1847+0810(cont), J1922+1530(cont).. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/aspen6/astronomy/sep00/ep038. 6. The jobs associated with the correlation of EP038 can be found at: /home/aspen6/astronomy/sep00/ep038/jobs. These files provided the correlator with all ancillary data needed for VLBI, including: correlation parameters and telescopes correlated in the final production. The job numbers are: 4220-4234 7. Operations staff have devised a web browser to navigate the file server aspen, as well as view and retrieve its text and PostScript files, gzipped or not. This browser can be reached through the VLBA homepage http://www.aoc.nrao.edu/vlba/html/VLBA.hmtl, initially under What's New but eventually under Observing. All of the files mentioned above can be accessed either with this browser or by FTPing to the vlbiobs account on aspen. Automated Calibration Transfer for VLBA Correlator Output --------------------------------------------------------- The first phase of automated calibration transfer for data from the VLBA correlator has been completed, and was used for your observation. This transfer of calibration information includes data from the 10 VLBA antennas, as well as selected information from the VLA and Effelsberg, which currently provide VLBA-style monitor data. Significant changes to AIPS have been required to introduce calibration transfer, so users must have the patched version of 15OCT98 AIPS, or any later version, beginning with 15APR99. Help files for a number of AIPS tasks have been updated to reflect the new calibration procedures. There also is a new version of the VLBI chapter of the AIPS cookbook, available from http://www.cv.nrao.edu/aips/aipsdoc.html, that includes more details on how to cope with the calibration transfer process. The calibration-transfer process relieves observers of the burden of creating and inputting calibration files for VLBA antennas. Instead, this information is now provided as tables attached to the FITS data sets output by the VLBA correlator. The ancillary data include antenna gain (GC table), system temperature (TY table), pulse calibration (PC table), flags (FG table), and weather (WX table). The wise observer will not modify these original tables; processing errors might then force the data to be reloaded using FITLD. See the description of MERGECAL in Section 9.2.1.7 of the new cookbook chapter for more detail. Of course, skeptical users can simply delete the appropriate tables created by FITLD and generate their tables in the old manner. Phase 2 of calibration transfer will include supply of data from more external telescopes, and probably will proceed incrementally, depending on both the availability of the external information and the implementation of new software in Socorro. At present, ancillary data from most external telescopes must still be loaded in the old manner, and observations of strong sources may be needed for manual pulse calibration at those telescopes. Up-to-date instructions on coping with observations including external telescopes can be found at http://www.nrao.edu/vlba/html/OBSERVING/cal-transfer/cal-transfer.html. Please send comments on calibration transfer to julvesta@nrao.edu, and send bug reports to daip@nrao.edu, with a copy to julvesta@nrao.edu. NOTES: NT: Playback weights are a little choppy throughout the observation. RFI at all stations; TR, JB & EB are worst. Very little fringing detected on any baselines except EB-TR from ~13:15 to ~23:30. Large fringe rates on EB-TR, EB-JB, and EB-ON baselines, starting around 00:05. From analysts@aoc.nrao.edu Thu Nov 2 16:12:44 2000 Date: Wed, 1 Nov 2000 09:20:40 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, reynolds@jive.nl, sjouwerma@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GG041 PI Letter Dear PI, We have examined the data for project GG041 on 05 Jun. 2000. The contact person for this project was Data Analysts. Here's a summary: 1. Tape weights vs. time plots have been generated for the entire time range of your experiment. These are a measure of tape record/playback quality, representing the fraction of valid data samples. Data with weights below 70-75% should be flagged. However, you may want to be more cautious when dealing with non-VLBA stations. The easiest way to estimate the best weight threshold is by looking at the tape weights vs. time plots generated here. You can find the weights plots at /home/aspen6/astronomy/jun00/gg041/sniffer/final/wtsfile.ps. If your experiment involves more than one distribution tape then there will be a tape# subdirectory between /final and wtsfile.ps. See /home/aspen6/README.sniffer for instructions on how to interpret this plot. 2. Delay, rate, phase, and amplitude plots were made for the observation. 3. Autocorrelation bandpass plots were generated for all antennas for scans on 3C84, 2048+312, 0014+813, 0336-019, 1614+051. 4. Cross-correlation bandpass plots were generated for all baselines to HN/EB for scans on 3C84, 2048+312, 0014+813, 0336-019, 1614+051. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/aspen6/astronomy/jun00/gg041. 6. The jobs associated with the correlation of GG041 can be found at: /home/aspen6/astronomy/jun00/gg041/jobs. These files provided the correlator with all ancillary data needed for VLBI, including: correlation parameters and telescopes correlated in the final production. The job numbers are: 9520-9534 7. Operations staff have devised a web browser to navigate the file server aspen, as well as view and retrieve its text and PostScript files, gzipped or not. This browser can be reached through the VLBA homepage http://www.aoc.nrao.edu/vlba/html/VLBA.hmtl, initially under Reports and Memos but then under Aspen. All of the files mentioned above can be accessed either with this browser or by FTPing to the vlbiobs account on aspen. Automated Calibration Transfer for VLBA Correlator Output --------------------------------------------------------- The first phase of automated calibration transfer for data from the VLBA correlator has been completed, and was used for your observation. This transfer of calibration information includes data from the 10 VLBA antennas, as well as selected information from the VLA and Effelsberg, which currently provide VLBA-style monitor data. Significant changes to AIPS have been required to introduce calibration transfer, so users must have the patched version of 15OCT98 AIPS, or any later version, beginning with 15APR99. Help files for a number of AIPS tasks have been updated to reflect the new calibration procedures. There also is a new version of the VLBI chapter of the AIPS cookbook, available from http://www.cv.nrao.edu/aips/aipsdoc.html, that includes more details on how to cope with the calibration transfer process. The calibration-transfer process relieves observers of the burden of creating and inputting calibration files for VLBA antennas. Instead, this information is now provided as tables attached to the FITS data sets output by the VLBA correlator. The ancillary data include antenna gain (GC table), system temperature (TY table), pulse calibration (PC table), flags (FG table), and weather (WX table). The wise observer will not modify these original tables; processing errors might then force the data to be reloaded using FITLD. See the description of MERGECAL in Section 9.2.1.7 of the new cookbook chapter for more detail. Of course, skeptical users can simply delete the appropriate tables created by FITLD and generate their tables in the old manner. Phase 2 of calibration transfer will include supply of data from more external telescopes, and probably will proceed incrementally, depending on both the availability of the external information and the implementation of new software in Socorro. At present, ancillary data from most external telescopes must still be loaded in the old manner, and observations of strong sources may be needed for manual pulse calibration at those telescopes. Up-to-date instructions on coping with observations including external telescopes can be found at http://www.nrao.edu/vlba/html/OBSERVING/cal-transfer/cal-transfer.html. Please send comments on calibration transfer to julvesta@nrao.edu, and send bug reports to daip@nrao.edu, with a copy to julvesta@nrao.edu. NOTES: VLBA Stations: SC: In Search at 3:20 - 4:10 UT. HN: OK NL: OK FD: Variable weights at 8:00 - 13:00 UT; weights are around 90%; recorder problem. LA: Did not observe due to communication problems. PT: Slightly variable weights at 13:00 - 19:00 UT. KP: OK OV: In Search at 1:30 - 2:05 UT, 3:15 - 4:15 UT, and 5:30 - 6:15 UT. BR: Variable weights at 0:00 - 13:00 UT; weights are around 90%; recorder problem. MK: Variable weights at 13:00 - 4:30; weights are around 75%; recorder problem. Non-VLBA Stations: JB: Tape in Search at 13:00 - 16:00 UT. Low amplitudes seen in IF channel 3 in the autocorrelation plots. EB: OK MC: Poor fringes on trans-atlantic baselines. NT: Variable weights at 14:00 - 18:00 UT; tape swapped with no improvement. WB: In Search at 14:30 - 15:30 UT and 4:00 - 6:00 UT; weights near 0%; tape moved with no improvement. Poor fringing at 19:15 - 21:45 UT From analysts@aoc.nrao.edu Mon Jul 2 12:05:32 2001 Date: Sun, 1 Jul 2001 17:50:13 -0600 (MDT) From: Data Analysts To: agg@jb.man.ac.uk, apolatid@oso.chalmers.se, foley@nfra.nl, glangsto@zia.aoc.NRAO.EDU, jive@jive.nl, kb@astro.uni.torun.pl, lister@hyaa.jpl.nasa.gov, p062gra@mpifr-bonn.mpg.de, support@dots.jpl.nasa.gov, trigilio@ira.noto.cnr.it, tuccari@ira.noto.cnr.it, vsog@vsop.isas.ac.jp Subject: W313B data Dear PI, We have examined the data for project W313B on 14 Sep. 2000. The contact person for this project was Data Analyst. Here's a summary: 1. Tape weights vs. time plots have been generated for the entire time range of your experiment. These are a measure of tape record/playback quality, representing the fraction of valid data samples. Data with weights below 70-75% should be flagged. However, you may want to be more cautious when dealing with non-VLBA stations. The easiest way to estimate the best weight threshold is by looking at the tape weights vs. time plots generated here. You can find the weights plots at /home/vlbiobs/astronomy/sep00/w313b/sniffer/final/wtsfile.ps. If your experiment involves more than one distribution tape then there will be a tape# subdirectory between /final and wtsfile.ps. See /home/vlbiobs/README.sniffer for instructions on how to interpret this plot. 2. Delay, rate, phase, and amplitude plots were made for the observation. 3. Autocorrelation bandpass plots were generated for all antennas for scans on all sources. 4. Cross-correlation bandpass plots were generated for all baselines to EB for scans on all sources. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/vlbiobs/astronomy/sep00/w313b. 6. The jobs associated with the correlation of W313B can be found at: /home/vlbiobs/astronomy/sep00/w313b/jobs. These files provided the correlator with all ancillary data needed for VLBI, including: correlation parameters and telescopes correlated in the final production. The job numbers are: 7220-7222, 7233-7236 7. Operations staff have devised a web browser to navigate the file server vlbiobs, as well as view and retrieve its text and PostScript files, gzipped or not. This browser can be reached through the VLBA homepage http://www.aoc.nrao.edu/vlba/html/VLBA.html, initially under Data Analyst but then under Aspen. All of the files mentioned above can be accessed either with this browser or by FTPing to the vlbiobs account on vlbiobs. NOTES: TR: Playback was good, and fringes were strong. NT: Playback was good, fringes were strong. Only anamoly seen was a mild spike in BBC 1 which could have been strong pcal. ON: Poor recording from 16:30 to 16:45 UT. Otherwise, good playback, with strong fringes. This station also had a mild spike in BBC 1, possibly strong pcal. EB: Computer problems were reported from 00:00 to 00:40 UT, all problems mentioned below are probably related to them. Playback was good, but these problems were seen: data missing from 23:00 to 00:30 UT, no fringes from 17:10 to 17:20 UT, and no fringes seen from 19:35 to 19:40 UT. JB: Fringes were strong, and playback was good, with the exception of a brief episode of shaky playback at 16:45 UT, lasting perhaps 10 minutes. WB: Poor recording from 20:30 to 21:00 UT, outside of this, recording was good. The bandwidth of this telescope isn't big enough to fill the correlator's bandwidth. Fringes were strong. Spacecraft: NZ and RZ tracked during this observation. Playback for all three tracking passes (2 by NZ, 1 by RZ) was good, and strong fringes were seen on all baselines, for at least a good part of the tracking passes. NZ pass 1: residual delay of 40 nsec, with a rate of 3 mHz were seen on the NZ-EB baseline. NZ pass 2: There was a clock jump at 22:00 UT, and a residual delay and rate of 30 to 70 nsec and -7 to 5 mHz (respectively) were seen on the NZ-EB baseline. RZ: On the RZ-JB baseline a residual delay of 50 to 80 nsec, and 0 to 40 mHz were seen. Discontinuities in the fringe signal on baselines to the Halca orbiter occur at each handoff from one tracking station to another, and at any dropouts in the phase-transfer link that occur during a tracking pass. Fringe fits should be broken at each such discontinuity to avoid de- correlation. This will happen automatically at handoffs because the tracking-station name assigned to Halca changes, but at link dropouts it is necessary to force an AIPS scan break by passing the following table to AIPS task INDXR via the INFILE adverb. SUBARRAY = 1 / 258 22:00:59.9 ! stn_id = NZ *!