RDV77 (Astrometric/Geodetic VLBA-77) 2009 October 7 18:00 Day 280 Notes prepared by David Gordon, John Gipson, and Ed Himwich, NVI/GSFC Special notes for this experiment ================================= This session will use 2-bit sampling for the first time in an RDV. The frequencies and channel bandwidths (8 MHz) are the same as in previous RDV's. The bit rate will increase from 128 Mbits/sec to 256 Mbits/sec. The 8 MHz, 2-bit sampling is preferable to 16 MHz, 1-bit sampling because the 16 MHz filters are not very good at the non-VLBA stations. The VLBA plans to correlate this session on both the hardware correlator and their new DiFX software correlator. We will analyze both versions at GSFC and make a detailed comparison of the two versions. This is in preparation for the VLBA's switchover to the software correlator early in 2010. The non-VLBA stations in this experiment (Hobart, Kokee, Ny Alesund, Wettzell, and Tsukuba) should see the "Special operations notes for non-VLBA stations" section below for special instructions. There are several nearly full network scans that can be used for 'fringe finding' at the correlator, located at the start, right after the Intensive break, in the middle, and at the end. It was not possible to have any full network scans with Hobart. Possible fringe finder scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Hn Ho Kk Kp La Mk Nl Ny Ov Pt Sc Ts Wz 1150+497 09280-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0657+172 09280-180759| 300 300 300 300 300 300 300 300 300 300 300 300 | 2007+777 09280-194554| 200 200 200 200 200 200 200 200 200 200 200 200 200 200 2007+777 09281-034311| 100 100 100 100 100 100 100 100 100 100 100 100 100 100| 2007+777 09281-114203| 100 100 100 100 100 100 100 100 100 100 100 100 100 100| 0912+029 09281-174506| 200 200 200 200 200 200 200 200 200 200 200 200 200 | 2007+777 09281-175527| 250 250 250 250 250 250 250 250 250 250 250 250 250 250| Additional Notes: - Two-bit sampling is used. - In this RDV, all stations will record on Mark5A, except Tsukuba. The Tsukuba data is later transferred to Mark5A. - The synch time for the VLBA correlator using Mark5 is ~25 seconds. Because of this, stations will start taking data 25 seconds prior to the normal scan time. They will continue to take data between scans if there is a gap of less than 25 seconds. - Wettzell and Kokee are absent from ~18:15 to ~19:45 because of the UT1 Intensive VLBI experiment. - The fluxes use our most recent models. Purpose ======= This is the fifth of six bi-monthly coordinated astrometric/geodetic experiments in 2009 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 and Bordeaux Observatory will perform 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 a small number of sources. While the quality of these results will be high, the observing and data reduction overhead required will be minimal because a small number of 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 from the pool of geodetic, astrometric, and monitoring 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. A small number of poorly observed and/or new requested sources may also be included to obtain or improve their positions. Schedule information ==================== This is a new schedule generated by David Gordon at GSFC using sked. Schedule file name: rdv77.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv77crd.br rdv77crd.fd rdv77crd.hn rdv77crd.kp rdv77crd.la rdv77crd.mk rdv77crd.nl rdv77crd.ov rdv77crd.pt rdv77crd.sc Summary file for correlator: rdv77.sksum Sked file: rdv77.skd Text file: rdv77.txt Vex file: rdv77.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2009/rdv77) Sked file: rdv77.skd Text file: rdv77.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: HOBART26, KOKEE, NYALES20, TSUKUB32, and WETTZELL. Total time: 1440 minutes ( 24.0 hours). Key: Br=BR-VLBA Fd=FD-VLBA Hn=HN-VLBA Ho=HOBART26 Kk=KOKEE Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Ts=TSUKUB32 Wz=WETTZELL Br Fd Hn Ho Kk Kp La Mk Nl Ny Ov Pt Sc Ts Wz Avg % obs. time: 45 48 44 25 42 48 48 43 47 51 46 48 48 34 48 44 % cal. time: 4 4 4 3 4 4 4 4 4 4 4 4 4 4 4 4 % slew time: 28 26 27 34 20 27 26 28 26 21 27 26 28 19 12 26 % idle time: 22 20 23 37 34 20 20 24 21 23 22 20 18 42 35 26 total # scans: 373 380 388 237 326 375 382 351 383 363 365 381 373 376 343 359 # scans/hour : 16 16 16 10 14 16 16 15 16 15 15 16 16 16 14 15 Avg scan (sec): 104 110 99 92 110 110 109 106 106 121 109 109 111 78 120 105 # data tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 # Mk5 tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16 16 Total GBytes: 1800 1917 1799 1044 1644 1896 1910 1717 1877 1977 1823 1912 1892 1455 1849 1768 Total GB(M5): 1600 1704 1599 928 1462 1685 1698 1526 1668 1757 1620 1700 1682 1293 1644 1571 Total GBytes (M5) recorded: 23566.6 # OF OBSERVATIONS BY BASELINE | Br Fd Hn Ho Kk Kp La Mk Nl Ny Ov Pt Sc Ts Wz StnTotal ------------------------------------------------------------------------------------- Br| 306 313 43 172 309 312 205 312 233 293 311 278 151 195 3433 Fd| 335 46 142 353 374 195 368 203 309 374 336 103 184 3628 Hn| 18 139 310 337 171 344 232 271 335 333 121 218 3477 Ho| 133 52 44 138 44 29 65 44 33 167 23 879 Kk| 159 142 274 141 126 181 143 117 196 95 2160 Kp| 354 213 346 186 329 355 310 113 163 3552 La| 195 373 208 309 380 337 107 189 3661 Mk| 193 110 239 196 167 192 72 2560 Nl| 213 304 371 343 109 193 3654 Ny| 160 207 194 188 302 2591 Ov| 310 271 130 136 3307 Pt| 335 106 187 3654 Sc| 78 189 3321 Ts| 152 1913 Wz| 2298 Number of 2-station scans: 136 Number of 3-station scans: 114 Number of 4-station scans: 98 Number of 5-station scans: 41 Number of 6-station scans: 18 Number of 7-station scans: 27 Number of 8-station scans: 31 Number of 9-station scans: 49 Number of 10-station scans: 63 Number of 11-station scans: 101 Number of 12-station scans: 38 Number of 13-station scans: 48 Number of 14-station scans: 27 Number of 15-station scans: 0 Total # of scans, observations: 791 22044 SOURCE SELECTION There are a total of 94 sources scheduled in this session. Among them, 30 sources are from the astrometric monitoring list and 50 are from the geodetic and monitoring list. Five non-geodetic sources with poorly determined ICRF2 positions are being re-observed to improve their positions. There are 9 new sources requested by L. Petrov. These 14 sources are observed in two scans each at the VLBA sites and sometimes at Hobart and Tsukuba. The goal is to accurately determine their coordinates. They are not optimized for imaging. 0627+814 06 37 43.38459 +81 25 27.7048 2000.0 0.0 Poor position 0857-329 08 59 20.81256 -33 09 24.7273 2000.0 0.0 Poor position 1817+157 18 19 38.28984 +15 43 44.7235 2000.0 0.0 Poor position 2005+372 20 07 45.40147 +37 22 02.2495 2000.0 0.0 Poor position 2039+037 20 42 14.50252 +03 56 13.9370 2000.0 0.0 Poor position 0110-361 01 13 15.85 -35 51 49.4 2000.0 0.0 J0113-3551/Petrov 0521-403 05 22 54.12 -40 20 31.0 2000.0 0.0 J0522-4020/Petrov 0705-412 07 06 43.04 -41 22 24.5 2000.0 0.0 J0706-4122/Petrov 0855+143 08 58 41.51 +14 09 43.8 2000.0 0.0 J0858+1409/3C212/Petrov 1232-338 12 34 46.23 -34 08 58.1 2000.0 0.0 J1234-3408/Petrov 0717-393 07 19 39.33 -39 28 49.2 2000.0 0.0 J1250-4432/Petrov 1622-310 16 25 55.51 -31 08 06.4 2000.0 0.0 J1625-3108/Petrov 2311-373 23 13 59.71 -37 04 47.1 2000.0 0.0 J2313-3704/Petrov 2348-432 23 51 34.96 -42 59 33.6 2000.0 0.0 J2351-4259/Petrov SCHEDULING ALGORITHMS This schedule uses the "SRCEVN SQRT" mode of Sked. 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. Recording Mode and Frequencies: NOTE: THERE ARE SOME CHANGES FROM PREVIOUS EXPERIMENTS FOR 2-BIT SAMPLING. ============================================================ The data will be recorded using the following setup: 8 channels 1:2 fan-out 16 MHz sample rate 2-bit sampling This recording mode is designated 256-8(RDV). There is no correlator speed-up factor. The frequency sequence covers 490 MHz at X-band and 140 MHz at S-band using 4 channels in each band. 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 total are available when observing with the VLBA stations, a wider spanned bandwidth is not advisable. 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. VLBA Kokee Chan Sky Tracks LO IF BBC | LO IF BBC # 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7600 A 805.99 3 2 X 8475.99 10,12,14,16 7900 B 575.99| 7600 A 875.99 4 3 X 8790.99 18,20,22,24 7900 B 890.99| 8100 C 690.99 5 4 X 8895.99 26,28,30,32 7900 B 995.99| 8100 C 795.99 6 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1500 B 732.99 9 6 S 2262.99 11,13,15,17 2900 A 637.01| 1500 B 762.99 10 7 S 2352.99 19,21,23,25 2900 A 547.01| 1500 B 852.99 13 8 S 2372.99 27,29,31,33 2900 A 527.01| 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 1 725.99 3 2 X 8475.99 10,12,14,16 7900 B 575.99| 7680 1 795.99 4 3 X 8790.99 18,20,22,24 7900 B 890.99| 8080 3 710.99 5 4 X 8895.99 26,28,30,32 7900 B 995.99| 8080 3 815.99 6 5 S 2232.99 3, 5, 7, 9 2900 A 667.01| 1600 2 632.99 9 6 S 2262.99 11,13,15,17 2900 A 637.01| 1600 2 662.99 10 7 S 2352.99 19,21,23,25 2900 A 547.01| 1600 2 752.99 13 8 S 2372.99 27,29,31,33 2900 A 527.01| 1600 2 772.99 14 VLBA | Hobart26, NyAlesund, Wettzell 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 3(H) 4 X 8895.99 26,28,30,32 7900 B 995.99| 8580.1 3 315.89 6 3(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 Special operations for non-VLBA stations: ========================================= Hobart, Ny Alesund, and Wettzell ================================================================== These stations have Mark IV racks. If you are using Field System 9.x or 10.x use the procedures and snap files generated by DRUDG. The IF3 command in the procedure IFDSX assumes that VC3 and VC10 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. The standard wiring is described in "help=if3". If you have questions about the wiring, please contact Brian Corey at Haystack. Kokee ================================================== This station has a VLBA4 back end. 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. Tsukuba ================================================== This station uses a K4-2 VC and K5 recorder. Use the procedures generated by DRUDG, be sure to set your rack type to K4-2, not K4-2/M4, if that change has not already been made. Please note you will need to comment out the incorrect VC commands in VCSX8 after the comment about these converters being present, but not used. This will corrected in future DRUDG release. The tpicd commands should be benign and do not need to be commented out unless they cause a problem. 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 the .snp file with DRUDG. 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. 7. Transfer your log files to your normal log file data center. The directories for three possible servers are listed below: ftp cddisa.gsfc.nasa.gov/ivsincoming directory on vlbeer: oct09 directory on aspen: /astronomy/oct09/rdv77 or /home/archive/e2e/archive/operations/VLBA/observe/oct09/rdv77 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. Disks should be shipped to Socorro as soon after the experiment as practical.