From analysts@aoc.nrao.edu Wed Jan 3 09:23:08 2001 Date: Fri, 22 Dec 2000 14:11:28 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, pwolken@jftl.jpl.nasa.gov, reynolds@jive.nl, tuccari@ira.noto.cnr.it, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GB037 P.I. Letter Dear PI, We have examined the data for project GB037 on 11 Nov. 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/nov00/gb037/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/nov00/gb037. 6. The jobs associated with the correlation of GB037 can be found at: /home/aspen6/astronomy/nov00/gb037/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: 8046;8034-8044 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.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 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: OK HN: Slightly variable weights. NL: OK FD: Tape in SEARCH at 3:00 - 3:30 UT and 3:50 - 4:45 UT. Highly variable weights at 3:00 - 9:00 UT; weights vary between 0% - 100%. This was a recorder problem. LA: OK PT: Snow on dish caused elevated system temperatures at the beginning of the observation. KP: Slightly variable weights. OV: Did not observe, 4 cm receiver was broken. BR: OK MK: Poor weights at 2:30 - 3:00 UT; weights around 85%. Non-VLBA Stations: EB: No fringes at 00:33 - 1:36 UT, 2:35 - 3:50 UT, and 5:30 - 6:00 UT. The telescope was stowed at these times during high winds. GO: OK MC: Data from 20:00 - 21:55 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. NT: No fringes in LCP channels. Data from 20:00 - 20:51 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. ON: Slightly variable weights at 00:30 - 7:00 UT. No fringes in LCP channels. RO: OK WB: Source beyond telescope limits after 4:31 UT; no fringes. Tracks 24 and 25 poor and dead at 00:50 - 1:25 UT; weights at 50%; tape was moved a couple of times with no improvement. Variable weights at 20:00 - 20:20 UT; weights vary between 80% - 100%. Channels 3,4,7,8 appear dead when tracks 24 and 25 are dead. Data from 20:00 - 20:56 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. Y: Nonlinear phase slope in IF channel 8 of cross-correlation plots. YB: Did not participate. From analysts@aoc.nrao.edu Mon Jan 8 17:06:37 2001 Date: Fri, 22 Dec 2000 14:11:28 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, pwolken@jftl.jpl.nasa.gov, reynolds@jive.nl, tuccari@ira.noto.cnr.it, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GB037 P.I. Letter Dear PI, We have examined the data for project GB037 on 11 Nov. 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/nov00/gb037/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/nov00/gb037. 6. The jobs associated with the correlation of GB037 can be found at: /home/aspen6/astronomy/nov00/gb037/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: 8046;8034-8044 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.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 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: OK HN: Slightly variable weights. NL: OK FD: Tape in SEARCH at 3:00 - 3:30 UT and 3:50 - 4:45 UT. Highly variable weights at 3:00 - 9:00 UT; weights vary between 0% - 100%. This was a recorder problem. LA: OK PT: Snow on dish caused elevated system temperatures at the beginning of the observation. KP: Slightly variable weights. OV: Did not observe, 4 cm receiver was broken. BR: OK MK: Poor weights at 2:30 - 3:00 UT; weights around 85%. Non-VLBA Stations: EB: No fringes at 00:33 - 1:36 UT, 2:35 - 3:50 UT, and 5:30 - 6:00 UT. The telescope was stowed at these times during high winds. GO: OK MC: Data from 20:00 - 21:55 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. NT: No fringes in LCP channels. Data from 20:00 - 20:51 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. ON: Slightly variable weights at 00:30 - 7:00 UT. No fringes in LCP channels. RO: OK WB: Source beyond telescope limits after 4:31 UT; no fringes. Tracks 24 and 25 poor and dead at 00:50 - 1:25 UT; weights at 50%; tape was moved a couple of times with no improvement. Variable weights at 20:00 - 20:20 UT; weights vary between 80% - 100%. Channels 3,4,7,8 appear dead when tracks 24 and 25 are dead. Data from 20:00 - 20:56 UT seems to be flagged in the FG table. The reason is unknown, but the data seems fine. So the observer may wish to unflag this time range or not use the provided flag table. Y: Nonlinear phase slope in IF channel 8 of cross-correlation plots. YB: Did not participate. From analysts@aoc.nrao.edu Tue Jan 16 14:49:21 2001 Date: Sun, 14 Jan 2001 13:56:00 -0700 (MST) From: Data Analysts To: agg@jb.man.ac.uk, apolatid@oso.chalmers.se, jive@nfra.nl, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, rap@sgra.jpl.nasa.gov, support@dots.jpl.nasa.gov, trigilio@ira.noto.cnr.it, tuccari@ira.noto.cnr.it, vsog@vsop.isas.ac.jp, xhuang@center.shao.ac.cn Subject: W312D data Dear PI, We have examined the data for project W312D on 17 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/w312d/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 JB 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/w312d. 6. The jobs associated with the correlation of W312D can be found at: /home/aspen6/astronomy/sep00/w312d/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: 3020-3031 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.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 aspen. NOTES: In General: All stations have fluctuating delays and rates, probably due to the source position. SH exhibits this the worst, so much so that the target source's delay and rate go outside of the window (at about 14:20 UT). SH: Playback was good. As mentioned above, the science source goes outside of the delay and rate window at 14:20 UT. Calibrator's look fine, therefore this is a source position related effect. ON: Poor recording on two reverse passes at: 6:30 and 7:45 UT. Otherwise, a success. TR: Poor recording from 14:15 to 15:00 UT. A change in playback drives offered no help. Otherwise good playback. There is a large bandpass spike in BBC 2 from 11:20 to 17:49, coupled with weak fringes in the APD/cross-correlation plots. NT: Poor recording from 17:30 to 18:15 UT. This was isolated. Otherwise, this station did well. EB: OK JB: OK. The feedback report states that the first 10 minutes of the observation could have been lost, but it looks OK to me. WB: This station performed well. Worth noting is that this observation exceeded the Tied Array's usable bandwidth. The data should be dealt with accordingly. Spacecraft: In general: RZ and GZ recorded with good playback. Fringes weren't seen at any time to any spacecraft baselines during the observation. UZ was scheduled to track, but a usable delta-t file was never provided, so it was left out of the correlation. 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 / 261 19:10:40.0 ! stn_id = GZ *! From analysts@aoc.nrao.edu Tue Jan 16 14:51:13 2001 Date: Wed, 10 Jan 2001 16:20:32 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@nfra.nl, p062gra@mpifr-bonn.mpg.de, reynolds@nfra.nl, sjouwerm@nfra.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbifriend@ira.noto.cnr.it Subject: GM040A PI Letter Dear PI, We have examined the data for project GM040A on 20 Nov. 2000. The contact person for this project was Joan Wrobel. 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/nov00/gm040a/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 LA 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/nov00/gm040a. 6. The jobs associated with the correlation of GM040A can be found at: /home/aspen6/astronomy/nov00/gm040a/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: 7838;7821-7837 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.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 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: Interesting rates and delays on some of the short baseline plots on scans of SN1993J. VLBA Stations: SC: Observing project BM143B at 10:08 - 13:30 UT; no data. RFI in IF channels 1, 2, 6 seen in the autocorrelation plots. HN: Occasionaly RFI in IF channels 7 and 8 seen in the autocorrelation plots. NL: In SEARCH at 11:35 - 15:10 UT and at 16:00 - 20:52 UT. Monitor data indicates that the tape was moving too slowly, only a few feet every several minutes during recording. Data lost due to this recorder problem. FD: The original correlation gave no fringes for NT with its first VLBI tape. This was traced to a cabling error in the playback drive used for that tape. Recorrelation recovered NT completely but at the cost of no data at FD from ~ 10:00 - 12:00 UT as the FD tape was no longer available for recorrelation. Weights at 0% at 12:05 - 12:35 UT; all tracks were poor; tape was swapped with no improvement. Variable weights at 18:15 - 18:45 UT; weights vary between 5% - 100%. RFI in IF channels 3 and 7 seen in autocorrelation plots. LA: RFI in IF channels 2, 3, and 8 seen in autocorrelation plots. PT: OK KP: RFI in IF channels 7 and 8. OV: Slight RFI in IF channels 7 and 8. BR: OK MK: RFI in IF channels 2, 3, 7, and 8 in autocorrelation plots. RFI showing up in cross-correlation plots in channel 7. Non-VLBA stations: EB: RFI in IF channels 3 of the autocorrelation plots. JB: Variable weights on forward passes from 10:08 - 16:52 UT; weights vary between 80% - 100%; tape swapped with no improvement. RFI seen in IF channels 1, 3, 5, 6, 7, and 8 of the autocorrelation plots. Low amplitudes and RFI spikes showing up in channels 6 and 8 in the cross-correlation plots. NT: RFI seen in IF channels 1, 2, and 3 of the autocorrelation plots. VLA27: Due to 50 MHz bandpass restrictions, there are no fringes in the first two channels, and there is a steeply sloped bandpass in channel 8. WB: Tape in Search at 10:10 - 10:35 UT; tape swapped with no improvement. From analysts@aoc.nrao.edu Tue Jan 23 12:21:49 2001 Date: Mon, 22 Jan 2001 14:33:51 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, reynolds@jive.nl, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbifriend@ira.noto.cnr.it Subject: GM040B PI letter Dear PI, We have examined the data for project GM040B on 24 Nov. 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/nov00/gm040b/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/nov00/gm040b. 6. The jobs associated with the correlation of GM040B can be found at: /home/aspen6/astronomy/nov00/gm040b/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: 2220-2233 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.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 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: Weights at 90% at 17:15 - 20:52 UT; recorder problem. Rain at site at 17:00 UT. HN: Slightly cyclical tsys values. NL: OK FD: Tape out of sync at 17:10 - 17:25 UT; tape was moved with no improvement. LA: OK PT: OK KP: OK OV: Weights at 95% at 11:30 - 15:45 UT; recorder problem. BR: OK MK: OK Non-VLBA stations: EB: OK JB: OK NT: Lower amplitudes seen in IF channels 6, 7, and 8 relative to the lower channels in the autocorrelation plots. VLA27: RFI seen in IF channel 1 of autocorrelation plots and channels 6, 7, and 8 have low sloping bandpasses. Poor fringing in channels 1, 7, and 8 due to 50 MHz total bandwidth limit. WB: OK From analysts@aoc.nrao.edu Tue Jan 23 12:21:57 2001 Date: Mon, 22 Jan 2001 16:08:03 -0700 (MST) From: Data Analysts To: foley@nfra.nl, 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, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GP028 PI Letter Dear PI, We have examined the data for project GP028 on 21 Nov. 2000. The contact person for this project was Leonid Kogan. 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/nov00/gp028/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/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/nov00/gp028. 6. The jobs associated with the correlation of GP028 can be found at: /home/aspen6/astronomy/nov00/gp028/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: 7920-7922;7963;7924-7933 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.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 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: RFI spike in IF channel 4 of autocorrelation plots. HN: First two IF channels are noiser than the last two channels at 20:45 UT. NL: RFI spikes in IF channels 1, 3, and 4. FD: OK LA: RFI spikes in all channels. PT: OK KP: Variable weights at 9:30 - 18:00 UT; weights vary between 80% - 100%; recorder problem. RFI spikes in IF channels 1, 2, and 4. OV: RFI spike in IF channel 4. BR: RFI spike in IF channel 4. MK: OK Non-VLBA stations: EB: OK JB: OK MC: RFI spikes in all channels. NT: Pcal spikes seen in plots. ON: Low amplitudes and weak fringes occasionally seen in IF channel 4 of cross-correlation plots. Tape lost vacuum at site at 7:16 - 7:45 UT and 9:39 - 10:22 UT; no data. Low weights at 13:30 - 14:10 UT; weights at 60%. TR: Some RFI showing up in the cross-correlation plots. RFI spikes in all channels. VLA27: OK WB: RFI spike in IF channel 1 of autocorrelation plots. From analysts@aoc.nrao.edu Tue Jan 23 12:22:06 2001 Date: Mon, 22 Jan 2001 16:24:11 -0700 (MST) From: Data Analysts To: foley@nfra.nl, 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@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: EP035 PI Letter Dear PI, We have examined the data for project EP035 on 21 Nov. 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/nov00/ep035/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/nov00/ep035. 6. The jobs associated with the correlation of EP035 can be found at: /home/aspen6/astronomy/nov00/ep035/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: 7720-7728;7734-7735;7742;7737-7740 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.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 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: In general: looks fine. Bad bits mostly due to site-specific problems, as detailed in station logs. RFI present at most sites, (EB is least affected) seen clearly in the autocorrelation bandpasses, not visible in cross spectra, so I imagine it is relatively harmless. Aviod auto-corr bandpass correction, obviously! CM: RCP, LCP at 1399MHz (second pair of IF's) seem to be partly outside the RF band - signal fades away in middle of BBC bandpass. They must know about this already. EB dead for sevaral hours, log says stowed for wind. JB off source about 2 hours, see log. WB off at 05:15 - 3C84 not visible, though it was at 28deg elevation. SCHED seemed to know about this, and it was in the log, so it is a known constraint but took me by surprize. ON: seems to have an intermittent problem with IF 4 and sometimes 3: weak/absent fringes. Likely to be playback related - the weights are very ragged. Hard to imagine it is a correlator problem and it is not much data, (05:15-05:40) so I am not asking for recorrelation. ON friend-of-telescope (Polatidis?) should investigate BBC/recorder hardware. Also first ON tape lost in shipment. Notes by Vivek Dhawan From analysts@aoc.nrao.edu Mon Feb 19 09:47:01 2001 Date: Fri, 16 Feb 2001 13:00:04 -0700 (MST) From: Data Analysts To: jive@jive.nl, p062gra@mpifr-bonn.mpg.de, reynolds@jive.nl, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbi@hut.fi, vlbi@jb.man.ac.uk, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it, xhuang@center.shao.ac.cn Subject: GM043A PI Letter Dear PI, We have examined the data for project GM043A on 09 Nov. 2000. The contact person for this project was M. Claussen. 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/nov00/gm043a/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 HN LA 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/nov00/gm043a. 6. The jobs associated with the correlation of GM043A can be found at: /home/aspen6/astronomy/nov00/gm043a/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: 4320 --- 4378 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.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 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: Playback/recording for this experiment was pretty reasonable. The most notable thing about the recording/playback was that Mh apparently had a recorder problem and the weights look very poor throughout the experiment. The field system at Eb was down from about 2000 UT to 2230 UT. A tape from Fd was inadvertenly degaussed which destroyed the data at the end of this run from that station (0430 - 0600 UT). Fd was stowed during the time approximately 2200 - 2300 UT to look into pointing error problems (see the VLBA operator log). Weather was a problem at many stations. At Mh, On, and Jb, rain was reported on the "Experiment Feedback" file. From the VLBA, the Tsys and weather data noted rain and/or high Tsys from Hn (0200 UT - end), Nl (beginning - 2000 UT), Ov (beginning - 2130 UT), Br (2030 - 0030 UT), and Mk (2000 - 2200 UT). In our "sniffer" plots, for the EVN only time, fringes were clearly seen on the calibrator from Eb to Mc, Jb, and Nt at times. We never saw fringes from Eb to Mh or Sh. Sometimes we saw fringes from Eb to On in IF 2, but never in IF1. Similar statements could be made for the spectral line source. For the VLBA only time, fringes were seen from La to all other stations on the calibrator, and spectral signatures in the cross- correlation plots were seen. In the autocorrelation plots from the EVN-only part of the experiment, On, Mc, Nt, Sh, and Jb had interference-looking signatures in the first 1/3 of the bandpass. In addition On and Jb had a ripple throughout the bandpass. At On both IFs had this ripple, but at Jb it was only pronounced in IF 1. Mh and Nt each had "birdies" near the center of both IF bandpasses, and these "birdies" were pretty consistent throughout the run. The IF 1 bandpass at Nt had a very strange shape. At Mc some long-wavelength ripples were seen in both bandpasses. For the VLBA-only part of the experiment, Kp had a low-level ripple in both IFs. From analysts@aoc.nrao.edu Thu Mar 1 10:18:15 2001 Date: Mon, 26 Feb 2001 15:13:21 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, pwolken@jftl.jpl.nasa.gov, reynolds@jive.nl, sjouwerm@jive.nl, tuccari@ira.noto.cnr.it, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@ira.noto.cnr.it Subject: GB038A PI Letter Dear PI, We have examined the data for project GB038A on 12 Nov. 2000. The contact person for this project was Michael Rupen. 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/nov00/gb038a/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 0954+658 and M81. 4. Cross-correlation bandpass plots were generated for all baselines to EB AND LA for scans on 0954+658 and M81. 5. Gzipped PostScript plots of Tsys and other monitor data for each available VLBA antenna can be found at /home/aspen6/astronomy/nov00/gb038a. 6. The jobs associated with the correlation of GB038A can be found at: /home/aspen6/astronomy/nov00/gb038a/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: 5220-5241 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.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 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: Variable weights at 12:30 - 14:15 UT; weights vary between 75% - 100%. HN: OK NL: OK FD: Poor weights at 9:30 - 12:30 UT; weights vary between 0% - 100%. This was a recorder problem. LA: OK PT: Snow degrades fringes around 17:00 UT. KP: RFI at S-band. OV: OK BR: OK MK: Weights at 90% at 14:15 - 14:40 UT. Non-VLBA stations: As expected, slightly different delays at EVN stations between S-band and X-band sections. Most stations have good fringes at X-band. Several EVN stations only fringe in RCP channels at S-band. EB: Recorder problems at site at 15:46 - 16:54 UT and 17:09 - 17:25 UT; no data. GO: Sloped bandpasses in IF channels 1 and 2 at S-band. Elevated amplitudes (200% from normal) in channels 2 and 5 of autocorrelation plots. MC: RFI at S-band in the lower four IF channels. NT: No fringes seen. Station is out of sync with other stations most of the observation. ON: OK RO: Fringes degrade after 14:00 UT. Sloped bandpass in channel 1 at S-band in autocorrelation plots. Low amplitude in IF channel 4 (75% from normal) at X-band. VLA27: Gaps during S-band scans; no S-band receivers. WB: Non-uniform bandpass in IF channel 6 at X-band.