From analysts@aoc.nrao.edu Mon Mar 26 09:40:41 2001 Date: Wed, 21 Mar 2001 09:48:45 -0700 (MST) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, reynolds@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbifriend@ira.noto.cnr.it Subject: GM040C PI Letter Dear PI, We have examined the data for project GM040C on 14 Feb. 2001. The contact person for this project was 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/vlbiobs/astronomy/feb01/gm040c/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,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/vlbiobs/astronomy/feb01/gm040c. 6. The jobs associated with the correlation of GM040C can be found at: /home/vlbiobs/astronomy/feb01/gm040c/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: 7120 - 7132 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. 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: Good playback, some small problems (see www.jive.nl/jivebin/jiveese) and MK was not observing due to snow. Y started late and has a spike in IF channel 1, and non-linear phases over the band in IF channels 1 and 8 (due to bandwidth). WB's hour angle limits prevent observing at the start and after 5h47m From analysts@aoc.nrao.edu Mon Mar 26 09:41:20 2001 Date: Wed, 21 Mar 2001 09:53:57 -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, 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: GO005B PI Letter Dear PI, We have examined the data for project GO005B on 13 Feb. 2001. The contact person for this project was 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/vlbiobs/astronomy/feb01/go005b/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 HN,MC 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/feb01/go005b. 6. The jobs associated with the correlation of GO005B can be found at: /home/vlbiobs/astronomy/feb01/go005b/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: 2420,2421,2431,2432,2423-2430 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. 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 the recording and playback are okay, except for CM which has 2 dead tracks resulting in 2 dead IF channels. Also the weights for CM until about 1:50 are zero; recorrelation did not help. A few hours of observing lost at JB and CM (see www.jive.nl/jivebin/jiveese) and at MK (5:24-9:46) due to ice. 3C286 and 3C236 do not fringe on the longest baselines. From analysts@aoc.nrao.edu Mon Mar 26 10:05:28 2001 Date: Wed, 21 Mar 2001 09:51:11 -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, tuccari@ira.noto.cnr.it, 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: GX007A PI Letter Dear PI, We have examined the data for project GX007A on 19 Feb. 2001. The contact person for this project was 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/vlbiobs/astronomy/feb01/gx007a/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 WB,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/vlbiobs/astronomy/feb01/gx007a. 6. The jobs associated with the correlation of GX007A can be found at: /home/vlbiobs/astronomy/feb01/gx007a/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: 7220-7243 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. 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: Project was correlated in one pass on 1030+074, at ra=10:33:34.0246 and dec=07:11:26.122 (J2000), taken from the schedule. Fringes were found on baselines to WB and HN, but unfortunately fringe finder scans were below many telescope limits - see the EVN feedback page www.jive.nl/jivebin/jiveese Recording and playback are in general good; remarks on individual stations: TR: the tape got damaged during correlation. Partly recovered with good weights SH, MC have RFI in IF-channels 1 and 2, JB in number 2 and LA in all four From analysts@aoc.nrao.edu Tue Apr 3 13:32:31 2001 Date: Sun, 1 Apr 2001 22:48:25 -0600 (MDT) From: Data Analysts To: agg@jb.man.ac.uk, foley@nfra.nl, glangsto@zia.aoc.NRAO.EDU, jive@jive.nl, kameno@hotaka.mtk.nao.ac.jp, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, support@dots.jpl.nasa.gov, trigilio@ira.noto.cnr.it, tventuri@astbo1.bo.cnr.it, vsog@vsop.isas.ac.jp, xhuang@center.shao.ac.cn Subject: W330V data Dear PI, We have examined the data for project W330V on 18 Nov. 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/nov00/w330v/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 MC 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/nov00/w330v. 6. The jobs associated with the correlation of W330V can be found at: /home/vlbiobs/astronomy/nov00/w330v/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: 5020-5029 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: SH: Playback was good. RFI spikes in both BBCs, continues until the end of the observation. Xc band fringes to MC rough to non-existent until 12:50 UT. NT: This station did well. TR: Poor recording from 10:00 to 10:30, 12:00 to 12:30, 20:50 to 21:20, and 21:45 to 22:00 (all times UT), a change in PBDs was no help. EB: Playback was good. Strong winds caused the telescope to stop observing at 20:07 UT, though the tape kept running. JB: Playback was good. RFI is intermittent over the course of the observation, both BBCs. It was strong enough to come through the cross-correlation plots. WB: Playback was good, except the tape was in search from 11:10 to 11:32 UT. Also worth noting: WB has a bandwidth of 8 MHz, but it was correlated at 16 MHz. MC: Playback was good, but there was no tape motion until 10:47 (when it should have started moving at 10:00) the reason for this is unknown. No fringes to to the APD plots from 13:30 to 13:40 UT, accompanied with low amplitudes. The reason for this is unknown. A large spike was seen starting at 10:48 UT, BBC 2, continuing for most of the time, until the end of the observation. Could be RFI or strong pcal. Spacecraft: TZ: Playback was good. Mild RFI in BBC 1. No fringes were seen to any other telescopes, for the whole tracking pass. RZ: Playback was good.Strong RFI in both BBCs. Fringes briefly with EB, at a residual rate and delay of: -20 nsec, from -30 to -20 mHz. NZ: Playback was good. Mild RFI in both BBCs. No fringes were seen on any baselines, for the whole tracking pass. 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 / 323 10:35:00.0 ! stn_id = TZ *! 323 11:31:30.0 ! stn_id = TZ *! 323 11:38:40.0 ! stn_id = TZ *! From analysts@aoc.nrao.edu Tue Apr 3 13:32:43 2001 Date: Mon, 2 Apr 2001 11:08:31 -0600 (MDT) From: Data Analysts To: jive@jive.nl, 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, xhuang@center.shao.ac.cn Subject: GM043C PI Letter Dear PI, We have examined the data for project GM043C on 01 Mar. 2001. 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/vlbiobs/astronomy/mar01/gm043c/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 HN,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/vlbiobs/astronomy/mar01/gm043c. 6. The jobs associated with the correlation of GM043C can be found at: /home/vlbiobs/astronomy/mar01/gm043c/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: 7520 - 7579 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. 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 Mc apparently had a recorder problem and the weights are fairly poor on forward passes throughout the experiment. There was about an hour (~1530 - 1630 UT) at Nt during which the tape wasn't moving. Mc had problems at the start of the schedule; lost the first hour. On only observed LCP; Eb had to stop several times because of snowfall - estimated times are in the Experiment Feedback log. Mh did not participate. There is a note in the VLBA operator log that Nl had a problem with an EL motor circuit breaker. There appears to be no problem with the antenna as we see fringes at all times. The site technician did remove the antenna from observing for about 20 minutes (1612 to 1635 UT) and indeed there are no fringes during that time. The weather was overcast low clouds, and fog for Kp. Tsys measurements are affected. There is a strange, slow Tsys excursion of 50 degrees in both IFs from at La from about 1430 to 2000 UT. It is so far unexplained. As in GM043a and GM043b, in the autocorrelation plots, the spectral "hash" that is seen in the first quarter or so of the bandpass from the MkIV stations is caused by the Socorro correlator correlating frame headers from the MkIV as data. This is described more fully in http://www.aoc.nrao/vlba/obstatus/guidelines.ps This only affects the autocorrelation spectra, not the cross correlation spectra, but it will probably spoil the autocorrelation spectra for use in amplitude calibration. There appears to be some radio frequency interference (RFI) at Nt near the center of the band in IF 1. It occurs throughout the experiment, and the amplitude is time variable. There is a low-level ripple in the autocorrelation bandpasses at Kp, more pronounced in IF 1. There are certainly fringes on the target source from Hn to VLBA stations, and even transcontinentally to Eb, Mc, and Nt. Not clear to Jb at the beginning, but fringes there later in the experiment. From analysts@aoc.nrao.edu Tue Apr 3 13:35:22 2001 Date: Mon, 2 Apr 2001 11:08:31 -0600 (MDT) From: Data Analysts To: jive@jive.nl, 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, xhuang@center.shao.ac.cn Subject: GM043C PI Letter Dear PI, We have examined the data for project GM043C on 01 Mar. 2001. 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/vlbiobs/astronomy/mar01/gm043c/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 HN,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/vlbiobs/astronomy/mar01/gm043c. 6. The jobs associated with the correlation of GM043C can be found at: /home/vlbiobs/astronomy/mar01/gm043c/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: 7520 - 7579 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. 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 Mc apparently had a recorder problem and the weights are fairly poor on forward passes throughout the experiment. There was about an hour (~1530 - 1630 UT) at Nt during which the tape wasn't moving. Mc had problems at the start of the schedule; lost the first hour. On only observed LCP; Eb had to stop several times because of snowfall - estimated times are in the Experiment Feedback log. Mh did not participate. There is a note in the VLBA operator log that Nl had a problem with an EL motor circuit breaker. There appears to be no problem with the antenna as we see fringes at all times. The site technician did remove the antenna from observing for about 20 minutes (1612 to 1635 UT) and indeed there are no fringes during that time. The weather was overcast low clouds, and fog for Kp. Tsys measurements are affected. There is a strange, slow Tsys excursion of 50 degrees in both IFs from at La from about 1430 to 2000 UT. It is so far unexplained. As in GM043a and GM043b, in the autocorrelation plots, the spectral "hash" that is seen in the first quarter or so of the bandpass from the MkIV stations is caused by the Socorro correlator correlating frame headers from the MkIV as data. This is described more fully in http://www.aoc.nrao/vlba/obstatus/guidelines.ps This only affects the autocorrelation spectra, not the cross correlation spectra, but it will probably spoil the autocorrelation spectra for use in amplitude calibration. There appears to be some radio frequency interference (RFI) at Nt near the center of the band in IF 1. It occurs throughout the experiment, and the amplitude is time variable. There is a low-level ripple in the autocorrelation bandpasses at Kp, more pronounced in IF 1. There are certainly fringes on the target source from Hn to VLBA stations, and even transcontinentally to Eb, Mc, and Nt. Not clear to Jb at the beginning, but fringes there later in the experiment. From analysts@aoc.nrao.edu Wed Apr 18 12:21:57 2001 Date: Tue, 10 Apr 2001 16:22:49 -0600 (MDT) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, p062gra@mpifr-bonn.mpg.de, pwolken@jftl.jpl.nasa.gov, reynolds@jive.nl, sjouwerma@jive.nl, tuccari@ira.noto.cnr.it, vlbi@jb.man.ac.uk, vlbi@oso.chalmers.se, vlbifriend@astbo1.bo.cnr.it, vlbifriend@bootes.hartrao.ac.za, vlbifriend@ira.noto.cnr.it Cc: lfoley@zia.aoc.NRAO.EDU Subject: GB036: PI letter Dear PI, We have examined the data for project GB036 on 22 Feb. 2001. 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/vlbiobs/astronomy/feb01/gb036/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, 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/vlbiobs/astronomy/feb01/gb036. 6. The jobs associated with the correlation of GB036 can be found at: /home/vlbiobs/astronomy/feb01/gb036/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: 7338 - 7351, 7356, 7353 - 7355 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. 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: MC: Playback was poor (weights ranged between 0% - 75%) on second tape, foward passes (~2:40 - ~7:45). A recorrelation showed no improvement. Also, RFI in channels 1,2,3,7,8. WB: Brief period of low weights, ~21:10 - ~21:20. Several attempts were made to improve playback. Also, channel 5 is dead. HH: Low playback weights, ~3:30 - ~4:45. This playback problem occured during recorrelation, and is not significant enough to warrant a third correlation. JB: Low playback weights initially (~21:10 - ~21:30 and ~21:55 - 22:15), several attempts to improve playback did not help. Channel 2 is dead until ~22:38. There is also significant RFI in all 8 channels. NT: Poor playback briefly, ~2:50 - 3:05, recorrelation showed no change. Channel 8 is dead. EB: Baselines to EB don't fringe as well after ~2:45, although the 6:38 scan of OQ208 is easily seen on trans-atlantic baselines. Tsys rises steeply around 8:00, probably due to low elevation angle. HN: Mildly poor playback on second tape, reverse passes, both correlations. RFI in channels 7 & 8. RO: Channels 1,3,5,7 are very weak. There is RFI in channel 4. SC: Somewhat variable playback. RFI in channels 7 & 8. GO: Amplitudes in channels 2 & 5 are twice as high as other channels. LA: RFI in channels 5,7,8. NL: Tsys is higher than nominal at first (low elevation), okay by ~3:00. Also, RFI in channels 7 & 8. OV: Tsys is higher than nominal at first, okay by ~4:30. RFI in channels 7 & 8. ON, Y, PT, MK: RFI in channels 7 & 8. From analysts@aoc.nrao.edu Wed Apr 18 12:23:26 2001 Date: Tue, 10 Apr 2001 16:36:14 -0600 (MDT) From: Data Analysts To: foley@nfra.nl, jive@jive.nl, kb@astro.uni.torun.pl, p062gra@mpifr-bonn.mpg.de, pwolken@jftl.jpl.nasa.gov, reynolds@jive.nl, sjouwerma@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: GM038 PI Letter Dear PI, We have examined the data for project GM038 on 23 Feb. 2001. 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/vlbiobs/astronomy/feb01/gm038/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 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/vlbiobs/astronomy/feb01/gm038. 6. The jobs associated with the correlation of GM038 can be found at: /home/vlbiobs/astronomy/feb01/gm038/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: 7420;7450;7422-7426;7451;7428-7430;7452-7453;7433;7454;7435;7455;7437;7456;7439-7448 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. 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 in IF channels 3 and 4 of the autocorrelation plots. HN: Small RFI spikes in IF channels 1 and 3 of the autocorrelation plots. NL: Slightly variable weights at 16:10 - 17:10; tape moved with no improvement. (See plots) Erroneous flagging occured in the data at roughly 20:25 - 21:15 UT, 23:15 - 23:30 UT, and 0:10 - 0:45 UT. Observer may want to undo this flagging to recover the data. FD: Small RFI spikes in all four IF channels. LA: Small RFI spikes in IF channels 1, 3, and 4. Noisy Tsys values around 1:30 - 5:00 UT due to rainy weather. PT: RFI in IF channels 3 and 4. KP: No data at 14:00 - 18:25 UT; antenna not operational due to elevation brake problem. RFI in IF channels 3 and 4. Lower bandpass edge spikes seen in all four IF channels in the autocorrelation plots. OV: Track #24 poor at 4:30 - 5:10 UT; weights at ~ 90%. RFI in IF channel 2. BR: Small RFI spikes in IF channel 1 and 2 of autocorrelation plots. Non-VLBA Stations: EB: No fringing during many large periods of time during the observation due to snowfall at the site (see the EVN feedback page). GO: Did not correlate since tape would not sync. Somehow old dates were recorded on the tape. JB: Track #21 poor at 18:20 - 19:40 UT; weights vary between 75% - 100%. Tape in SEARCH at 00:54 - 2:40 UT; there was a vacuum loss at the site at this time. Tape in SEARCH again at ~ 2:50 - 3:20 UT. Severe RFI in all four IFs of autocorrelation plots (See plots). RFI seen in the cross-correlation plots. MC: RFI in IF channel 3 of autocorrelation plots. NT: OK ON: Tape displayed variable weights and was in and out of SEARCH throughout correlate; tape was swapped a couple times with no improvements; weights vary between 0% - 100%; most tracks were weak. Tape lost vacuum at the site at ~2:45 UT; no data after this time. RO: Track #24 dead at 19:45 - 20:00 UT; weights at 75%. Fringes seen in LCP channels only. RO does not have RCP channels. RFI seen in the cross-correlation plots. TR: No fringes seen in plots; reason unknown. RFI in IF channels 2, 3, and 4 of autocorrelation plots. Second tape never arrived. It was lost in transit. Data lost from 00:57 - 8:00 UT. VLA1: Variable weights on most tracks at 18:30 - 19:30 UT, and 4:00 - 4:50 UT; tape moved with no improvements. RFI in IF channels 3 and 4. WB: OK