From analysts@aoc.nrao.edu Wed Jun 21 11:11:13 2000 Date: Mon, 19 Jun 2000 15:01:52 -0600 (MDT) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbifriend@astbo1.bo.cnr.it, vlbifriend@bootes.hartrao.ac.za, vlbifriend@ira.noto.cnr.it Subject: GP025C P.I. Letter Dear PI, We have examined the data for project GP025C on 27 May 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/may00/gp025c/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 J1907+0127, 1910+052, J2025+0316, 2022+031, J2101+0341, 2059+034, and 3C454.3. 4. Cross-correlation bandpass plots were generated for all baselines to HN for scans on J1907+0127, 1910+052, J2025+0316, 2022+031, J2101+0341, 2059+034, and 3C454.3. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/aspen6/astronomy/may00/gp025c. 6. The jobs associated with the correlation of GP025C can be found at: /home/aspen6/astronomy/may00/gp025c/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: 2820-2826 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: VLBA Stations: SC: Slightly noisy system temperatures in IF channels 1 and 3. This is possibly RFI. Pcals cross-correlating at 5:29 UT on the HN-SC baseline. HN: OK NL: OK FD: OK LA: Did not observe due to communication problems during the aftermath of forest fire. PT: OK KP: OK OV: OK BR: OK MK: In SEARCH at 7:46 - 9:15 UT. Recorder problem. Non-VLBA Stations: EB: In SEARCH at 21:30 - 22:30 UT; tape moved with no improvement. HH: Poor weights at 21:30 - 21:55 UT; weights vary between 0% - 100%. MC: Poor weights on track 5 and 6 at 21:30 - 22:05 UT; weights at 50%; tape was moved with no improvement. Lower bandpass edge spike in IF channels 1 and 2 in autocorrelation plots. NT: Variable weights at 22:15 - 22:30 UT; weights vary around 75%. ON: Did not observe due to high winds. TR: In SEARCH at 22:20 - 22:50 UT. Lower bandpass edge spike seen in IF channel 2 of autocorrelation plots. RFI spike in IF channel 4. WB: Typical peaked bandpasses in autocorrelation plots. From analysts@aoc.nrao.edu Mon Jul 17 12:23:23 2000 Date: Fri, 14 Jul 2000 11:00:05 -0600 (MDT) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GO003A P.I. Letter Dear PI, We have examined the data for project GO003A on 26 May 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/may00/go003a/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 HN AND 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/may00/go003a. 6. The jobs associated with the correlation of GO003A can be found at: /home/aspen6/astronomy/may00/go003a/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: 4620-4636 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: EB: Tape in search until 22:35 UT due to some recording problems at the site (See EVN feed back page). WB is down around 12 UT (See EVN feedback for this and other time ranges with problems). MK is down for a few large time periods due to poor weather at the site (See VLBA operators log.) Some stations (TR,MC,PT,NT, and KP) exhibit short durations of low weights. JB has a low amplitude in IF channel 3 (roughly 25%) in the autocorrelation plots. RFI seen in IF channels 1 and 2 at MC, IF channel 1 at TR, and IF channel 1, 2, and 4 at JB. Some RFI leaks into the cross-correlation plots, especially IF channel 1 at MC. MC IF channel 1 is dead at 8:41 - 8:53 UT. IF channel 4 at TR is dead at 12:00 and 13:35 UT, and IF channel 1 and 3 at TR are dead at 17:16 UT. Steep phase slope across bands seen on the MC-WB baseline @ 1:14 UT in the cross-correlation plots. Some RFI on the MC-TR baseline is affecting fringes in the apd plots at roughly 0:00 - 2:00 UT. SC seems to have slightly low amplitudes in the apd plot From analysts@aoc.nrao.edu Thu Jul 27 11:50:04 2000 Date: Wed, 26 Jul 2000 13:13:12 -0600 (MDT) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, sjouwerm@jive.nl, tuccari@ira.noto.it, vlbi@jb.man.ac.uk, vlbifriend@ira.noto.cnr.it Subject: GM035F P.I. Letter Dear PI, We have examined the data for project GM035F on 06 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/gm035f/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 HN 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/jun00/gm035f. 6. The jobs associated with the correlation of GM035F can be found at: /home/aspen6/astronomy/jun00/gm035f/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: 2420-2432 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: VLBA Stations: SC: Intermittently poor weights at 20:50 - 00:14 UT. Weights dip briefly to around 85%. High number tracks reported poor readbacks during recording. Weights are mostly at 100%. HN: Noisy system temperatures recorded due to rain during observation. NL: OK FD: Poor weights and in SEARCH at 13:48 - 20:45; weights vary between 0% - 100%. This was a tape and recorder problem. LA: OK PT: OK KP: Poor weights at 22:00 - 23:15 UT, then in SEARCH at 23:15 - 00:14 UT. Recorder problem. OV: OK BR: Poor weights at 13:48 - 20:45; weights vary around 60% -80%. This was a tape problem. Noisy system temperature recorded at 20:30 - 22:00 UT. MK: OK Non-VLBA Stations: EB: OK JB: OK NT: Highly sloped bandpass in IF channel 1 of autocorrelation plots. RFI spike in IF channel 2. VLA27: Large RFI spike seen in IF channel 1 in the autocorrelation plots. Sloped bandpass and low amplitude in IF channels 7 and 8. Non-linear phase slopes in IF channels 1 and 7. No fringing in IF channel 8. This due to these channels being on the edge or outside of the VLAs 50 MHz bandpass. WB: Slightly variable weights at 19:00 - 20:00 UT.