rdv51 (Astrometric/Geodetic VLBA-50) 2005 June 29 Notes prepared by John Gipson, NVI/GSFC Schedule name: rdv51.skd Pointing files: rdv51crd.br, rdv51crd.fd, rdv51crd.hn, rdv51crd.kp, rdv51crd.la, rdv51crd.mk, rdv51crd.nl, rdv51crd.ov, rdv51crd.pt, rdv51crd.sc ftp://vlbiobs@aspen.nrao.edu/home/aspen6/astronomy/jun05/rdv51 Summary file for correlator: rdv51.sksum on aspen PCFS file: ftp://vlbigeo@cddisa.gsfc.nasa.gov/vlbigeo/jun05/rdv51.skd http://lupus.gsfc.nasa.gov/sess/2005/sesshtml/rdv51.html First observations: name yyddd-hhmmss 4C39.25 05180-180000| Ap Br Fd Gc Hn Kp La Nl Ov Pt Sc Tc Wf 1334-127 05180-180543| HH 1418+546 05180-180601| GG 0454+844 05180-180641| Mk 3C147 05180-200051| Wz Last observations: name yyddd-hhmmss 0656+082 05181-173934| Mk Gg Wf 0607-157 05181-174643| Ap 1606+106 05181-174752| Wz 4C39.25 05181-175313| Br Fd Gc Hn Kp La Nl Ov Pt Sc 1236-684 05181-175318| Hh Tc Summary statistics: Key: Ap=ALGOPARK Br=BR-VLBA Fd=FD-VLBA Gc=GILCREEK Hh=HARTRAO Hn=HN-VLBA Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Gg=ORION_5M Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Tc=TIGO Wf=WESTFORD Wz=WETTZELL Ap Br Fd Gc Hh Hn Kp La Mk % obs. time: 32 72 73 67 45 74 73 75 63 % cal. time: 3 3 3 3 2 3 3 3 3 % slew time: 57 19 19 15 27 17 19 18 17 % idle time: 7 5 4 14 25 5 3 3 16 total # scans: 231 264 263 219 136 250 265 263 217 # scans/hour : 9.6 11.0 10.9 9.1 5.6 10.4 11.0 10.9 9.0 Avg scan (sec): 121 237 240 265 286 256 240 246 253 Total GBytes: 520 1129 1134 1061 717 1153 1146 1166 987 Total GB(M5): 462 1003 1008 943 637 1025 1019 1037 877 # of tapes : 2.1 2.4 2.4 2.5 2.1 2.4 2.4 2.4 2.4 tape change times (hhmm): 0511 0417 0416 0327 0537 0418 0416 0416 0416 1615 1436 1436 1325 1706 1436 1436 1436 1439 Nl Gg Ov Pt Sc Tc Wf Wz Avg % obs. time: 74 66 72 74 68 60 74 56 66 % cal. time: 3 3 3 3 3 1 3 2 3 % slew time: 17 6 19 19 19 5 10 6 19 % idle time: 4 24 5 3 10 32 13 35 13 total # scans: 255 226 260 266 232 124 221 171 227 # scans/hour : 10.6 9.4 10.8 11.0 9.6 5.1 9.2 7.1 9.4 Avg scan (sec): 252 253 241 241 254 421 290 284 257 Total GBytes: 1159 1044 1130 1157 1063 957 1172 890 1034 Total GB(M5): 1030 928 1004 1028 945 851 1042 791 919 # of tapes : 2.4 2.1 2.4 2.4 2.4 2.1 2.2 2.0 tape change time 0416 0542 0416 0416 0416 0545 0453 0710 1436 1708 1436 1436 1436 1653 1543 0000 Total number of tapes: 38.8 Total GBytes (M5) recorded: 15630.0 # OF OBSERVATIONS BY BASELINE | Ap Br Fd Gc Hh Hn Kp La Mk Nl Gg Ov Pt Sc Tc Wf Wz StnTotal ---------------------------------------------------------------------------------- Ap|231 131 126 101 12 192 123 134 85 158 133 116 126 133 25 154 52 1801 Br| 264 185 175 5 144 195 197 157 182 120 213 199 118 23 123 55 2222 Fd| 263 132 4 140 241 237 147 206 134 214 245 148 41 129 41 2370 Gc| 219 6 111 139 132 128 131 99 145 139 86 10 105 69 1708 Hh| 136 15 4 5 0 5 14 1 4 17 52 11 72 227 Hn| 250 137 152 91 179 145 128 142 162 23 191 72 2024 Kp| 265 242 162 200 124 227 256 135 39 124 44 2392 La| 263 148 217 128 221 250 143 39 133 46 2424 Mk| 217 125 84 174 157 85 34 80 25 1682 Nl| 255 139 182 206 152 31 156 60 2329 Gg| 226 120 130 126 38 149 54 1737 Ov| 260 228 127 31 112 41 2280 Pt| 266 137 39 127 45 2430 Sc| 232 46 145 59 1819 Tc| 124 25 10 506 Wf| 221 73 1837 Wz| 171 818 Number of 2-station scans: 197 Number of 3-station scans: 82 Number of 4-station scans: 44 Number of 5-station scans: 37 Number of 6-station scans: 29 Number of 7-station scans: 37 Number of 8-station scans: 35 Number of 9-station scans: 35 Number of 10-station scans: 20 Number of 11-station scans: 22 Number of 12-station scans: 21 Number of 13-station scans: 32 Number of 14-station scans: 42 Number of 15-station scans: 8 Number of 16-station scans: 1 Number of 17-station scans: 0 Total # of scans, observations: 642 15303 Special Notes for this session: - Most stations participate in two initial long (5-min) scans and a final 5-min scans. - GGAO was tagged along in the schedule. - Wettzell starts at 20:00:00 because of the intensive. - NEW in rdv46. We have used a new algorithm for selecting the sources. - The fluxes used our most current models. If we did not have models for the fluxes we used those determined by Alan Fey (USNO). Purpose ======= This is the 3rd of six bi-monthly coordinated astrometric/geodetic experiments in 2005 that use the full 10-station VLBA plus up to 10 geodetic stations capable of recording VLBA modes. This year's series is a continuation of the highly successful RDV series begun in 1997. These experiments are being coordinated by the geodetic VLBI programs of three agencies: USNO, NASA, and NRAO. The experiments have been designed so that the same data set may be used by each agency for its particular goals. USNO will perform repeated imaging and correction for source structure. These sources will establish a set of core reference sources with known structure and precisely known positions. These data will provide the basis for evaluating the long term stability of the radio reference frame and the ultimate accuracy of wide angle astrometric measurements of extragalactic radio sources using VLBI. NASA will analyze this data to determine a high accuracy terrestrial reference frame. The data will incorporate the VLBA stations into the VLBI reference frame through the inclusion of other geodetic stations for which we have long histories. The data will also produce the most accurate Earth rotation results ever produced. We will use these data to make accurate absolute measurements of UT1. NRAO will use these sessions to provide a service to users who require high quality positions for small numbers of sources. While the quality of these results will be high, the observing and data reduction overhead required will be minimal because such sources can be incorporated into a session of the regular geodetic observations, instead of requiring special observations. Sources for this series of experiments will be selected using the proposed approach. For each experiment we will select a set of 70-80 sources out of the pool of ~400 Northern Hemisphere ICRF sources. About 40-50 of these will remain the same from experiment to experiment and will be chosen to optimize the goals of the three groups. Schedule ======== This is a new schedule generated by John Gipson using sked. In addition to the VLBA, the session also uses: Ap=ALGOPARK Gc=GILCREEK Hh=HARTRAO Gg=ORION_5M Ov=OV-VLBA Tc=TIGO Wz=WETTZELL SOURCE SELECTION There are a total of 100 sources in this session. 26 sources were chosen because they had not been observed recently in the RDVs. 4 sources were requested sources: 2250+194 Lebach. Observed regularly since RDV36 3C454.3 Interesting shource whose brightness has changed dramatically. J074+21 Leonid Gurvits 1829-207 David Boboltz The remaing 70 sources were chosen from the geodetic catalog to complement the sky distribution of the above sources. SCHEDULING ALGORITHMS This schedule also uses the "SRCEVN SQRT" mode. In the absense of any constraints, Sked will preferentially observe strong sources that have high visibility. This mode attempts to smooth out the number of observations per source. Because of mutual visibility constraints, Hartrao has fewer observations than the other stations. To maximize the number of observations involving Hartrao, scans involving this station were prefered. The VLBA stations routinely use automatic tape allocation and automatic tape reversal. Recording Mode and Frequencies: same as previous experiments ============================================================ The data will be recorded using the following setup: 8 channels 1:4 fan-out 16 MHz sample rate 1-bit sampling This recording mode is designated 128-8-1. The correlator speed-up factor is 2. The frequency sequence covers 500 MHz in 8 channels. This span fits in one VLBA receiver passband but it uses both the high and low parts of the geodetic receivers. Because only 8 channels are available when observing with the VLBA stations, a wider spanned bandwidth is not advisable. With the 1:4 fanout at 16 MHz sample rate, all 32 tracks are recorded in one pass, so there will be 14 passes on a tape. Special note for sessions starting with RDV36: The S-band frequency sequence was increased by 7 MHz from RDV35. This was done to put the third S-band channel 7 MHz above the DARS band (2220-2245Mz.) These tables list the setup for the VLBA stations, the geodetic stations with VLBA back ends, and the geodetic stations with Mark IV back ends. These are the SAME frequencies used in all the standard RDV sessions. Geodetic stations: please read the special procedures in the next section! VLBA Fairbanks Kokee Chan Sky Tracks LO IF BBC | LO IF BBC #| LO IF BBC # 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7600.1 A 805.89 3|7600 A 805.99 3 2 X 8475.99 10,12,14,16 7900 B 575.99| 7600.1 A 875.89 4|7600 A 875.99 4 3 X 8790.99 18,20,22,24 7900 B 890.99| 8080.0 C 710.99 5|8100 C 690.99 5 4 X 8895.99 26,28,30,32 7900 B 995.99| 8080.0 C 815.99 6|8100 C 795.99 6 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1540.1 B 692.89 9|1500 B 732.99 9 6 S 2262.99 11,13,15,17 2900 A 637.01| 1540.1 B 722.89 10|1500 B 762.99 10 7 S 2352.99 19,21,23,25 2900 A 547.01| 1540.1 B 812.89 13|1500 B 852.99 13 8 S 2372.99 27,29,31,33 2900 A 527.01| 1540.1 B 832.89 14|1500 B 872.99 14 VLBA | Tsukuba Chan Sky Tracks LO IF BBC | LO IF BBC # 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7680 A 725.99 3 2 X 8475.99 10,12,14,16 7900 B 575.99| 7680 A 795.99 4 3 X 8790.99 18,20,22,24 7900 B 890.99| 8080 A 710.99 5 4 X 8895.99 26,28,30,32 7900 B 995.99| 8080 A 815.99 6 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1600 B 632.99 9 6 S 2262.99 11,13,15,17 2900 A 637.01| 1600 B 662.99 10 7 S 2352.99 19,21,23,25 2900 A 547.01| 1600 B 752.99 13 8 S 2372.99 27,29,31,33 2900 A 527.01| 1600 B 772.99 14 Medicina, Wettzell, Matera, GGAO, TIGO VLBA | Westford, NOTO, HartRAO, Onsala Chan Sky Tracks LO IF BBC | LO IF VC VC# Patch 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 8080.0 1 325.99 3 H 2 X 8475.99 10,12,14,16 7900 B 575.99| 8080.0 1 395.99 4 H 3 X 8790.99 18,20,22,24 7900 B 890.99| 8580.1 3 210.89 5 L 4 X 8895.99 26,28,30,32 7900 B 995.99| 8580.1 3 315.89 6 H 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 2020.0 2 212.99 9 H 6 S 2262.99 11,13,15,17 2900 A 637.01| 2020.0 2 242.99 10 H 7 S 2352.99 19,21,23,25 2900 A 547.01| 2020.0 2 332.99 13 H 8 S 2372.99 27,29,31,33 2900 A 527.01| 2020.0 2 352.99 14 H Procedures ========== With continuous tape motion, the tape starts moving and recording at the beginning of the first scan of a pass. The tape runs and records continuously thereafter to the end of the tape (EOT or BOT). A parity check is done after the tape reaches this point. The tape starts moving in the opposite direction at the early start time (30 seconds) before the next scan. There will be a variable length of time between tape passes. For the VLBA stations, there will normally be a long enough time gap between passes for playback. Special procedures for non-VLBA stations ======================================== The tape motion in this experiment is different from normal start&stop schedules. At the time the antenna gets on source, you should see the command "data_valid=on" from the SNAP schedule. This is the signal that the VLBA correlator will use to determine when to start correlating this scan. At the time the antenna begins slewing to the next source, you will see the command "data_valid=off" from the schedule. This is the signal the correlator will use to stop correlating that scan. There will be no "et" command at the end of a scan. The DRUDG listing has a column that lists the time that the tape will stop. Note the "Start Tape" and "Stop Tape" columns list times only when the tape will start or stop, otherwise the time is blanked out because the tape is moving. For each scan, the "Start Data" column will be the time when the antenna is expected to be on source. The "Stop Data" column is the time when the antenna starts slewing to the next source. After the setup procedure, the tape is started at the beginning of each pass and will continue to move, at record speed, until it reaches the end of the pass. There are no fast tape motions in this schedule. The tape is continuously recording from the initial "st" command at the start of the pass. There are no other "st" commands during a pass and there are no other setup procedures called. If you have to re-start the schedule for a problem or emergency, you will be able to do it either 1) at the beginning of a pass or 2) in the middle of a pass by entering the setup and start tape commands manually. The problem is that the heads cannot be positioned reliably when the tape is moving if there is recorded data on the tape. If the tape is moving the reproduce power level can cause cross-talk with the head positioner and give false indications of position. Another problem is that the data disappears on tape while the formatter resets itself, thus largely eiliminating the benefits of continuous motion. At the end of each pass a parity check is done. You will need procedures named "checkf80" and "checkr80". Check and adjust the timing of this procedure and then make sure it can complete in the 100 seconds that the schedule allows. Special procedures for Medicina, Westford, Onsala, Wettzell, Tsukuba, Matera, GGAO, TIGO ================================================================== These stations have Mark IV formatters. Use the procedures generated by DRUDG. These must be generated for rdv51 because of the new S-band frequency sequence. Note that the patching for VC10 must be changed from L to H for this session. This is a non-standard setup. There are 8 video converters used: 3, 4, 5, 6, 9, 10, 13, and 14. These were selected so that you will NOT have to change the standard geodetic IF patching. The 6 unused VCs 1, 2, 7, 8, 11, and 12 should be set to frequencies which do not occur in any of the passbands. Any value in the 100-200 MHz range is OK. The Mark IV formatters now have barrel roll capability, so please verify that your FORM command has specification for barrel roll. The IF3 command in the procedure IFDSX assumes that VC3 will be patched to High. Please verify that the switches for your IF3 module are wired this way, and if they are not please edit the IF3 command to change the switches. If you have questions about the wiring, please contact Brian Corey at Haystack. Special procedures for Kokee ================================================== These stations have VLBA back ends. Use the procedures generated by DRUDG. BBCs 3,4,5,6 are used at X-band with IFs A and C. BBCs 9,10,13,14 are used at S-band with IF B. The unused BBCs 1,2,7,8,11,12 should be set to frequencies which do not occur in any of the passbands. Any value in the range 500-600 MHz is OK. The formatter should be set up to use barrel roll. Please verify that you are using the same barrel roll as you used in previous sessions correlated at the VLBA. CHECKLIST for non-VLBA stations =============================== Please follow the checklist below to ensure you have done all the necessary steps for this experiment: 1. Make .prc file with DRUDG and check them out, or use the procedures from last session. Check out parity check procedures. 2. Make .snp file and listings using DRUDG options 3 and 5. 3. Set up your system to monitor the clocks with the "gps-fmout" or "fmout-gps" commands. If you have questions about this, please contact Ed Himwich as soon as possible. 4. Send a "ready" message an hour or so before the experiment to the ivs-ops mail list. Copy analysts@nrao.edu on your ready message. 5. Send a "start" message soon after you have started recording. Copy analysts@nrao.edu on the message. 6. At the end of the experiment, send a "finish" message summarizing how the experiment was conducted. Copy analysts@nrao.edu on your message. 8. Transfer your log files to your normal log file data center. The directories for three possible servers are listed below: directory on cddisa: jun05 directory on vlbeer: jun05 directory on aspen: /home/aspen6/astronomy/jun05/rdv51 NOTE: If you don't normally use aspen, you should not put your log file on that server. The VLBA correlator knows where to find your log files. Correlation =========== This experiment will be correlated at the VLBA Correlator. Tapes should be shipped to Socorro as soon after the experiment as practical.