RDV88 (Astrometric/Geodetic VLBA-88) 2011 AUG 2 17:30 DOY 214 Notes prepared by David Gordon, John Gipson and Ed Himwich NVI/GSFC Special notes for this experiment ================================= This session will use 2-bit sampling again, as in the last few RDV's. Frequencies and channel bandwidths (8 MHz) are the same as in previous RDV's. The bit rate will be 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 data will be correlated at the VLBA using the DiFX software correlator. There are 5 non-VLBA stations scheduled (FORTLEZA, HARTRAO, NYALES20, TSUKUB32, and WETTZELL). These stations should see the "Special operations notes for non-VLBA stations" section below for special instructions. With the wide distribution of stations, it is not possible to get all the stations in a single scan. However, the schedule has two long (300 second) scans each at the beginning and near the end which contain all the stations. These are designed to facilitate fringe finding at the VLBA correlator. All stations please try to be onsource and recording data for these first scans. There are also several scans in the middle with all but one or two of the stations that could also be used as fringe finders. These scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Ft Hh Hn Kp La Mk Nl Ny Ov Pt Sc Ts Wz 1803+784 11214-173000| 300 300 300 300 300 300 300 300 300 300 300 300 300| 1156+295 11214-173654| 300 300 300 300 300 300 300 300 300 300 300 300 300| 1130+009 11214-174413| 480 480 480 480 480 480 480 480 480 480 480 480 480| 0805+410 11214-180356| 199 183 480 157 196 183 376 165 480 204 187 154 480| 3C274 11214-202130| 164 104 286 103 158 154 227 104 286 162 157 56 196| 1803+784 11215-000220| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1739+522 11215-034128| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 2250+194 11215-043334| 480 480 480 480 480 480 480 480 480 480 480 313 480| 3C418 11215-070850| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1803+784 11215-072011| 45 45 45 45 45 45 45 45 45 45 45 45 45| 2229+695 11215-072150| 45 45 45 45 45 46 45 54 45 45 45 45 54| 0536+145 11215-114737| 480 480 480 480 480 480 480 480 480 480 480 480 480| 0133+476 11215-122711| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1015+057 11215-165018| 480 459 480 480 438 476 448 451 480 480 462 423 480| 1803+784 11215-171549| 300 300 300 300 300 300 300 300 300 300 300 300 300| 1156+295 11215-172240| 300 300 300 300 300 300 300 300 300 300 300 300| Additional Notes: - Two-bit sampling is used. - In this RDV, all stations will record on Mark5A/B, except Tsukuba. Tsukuba will record on K5 and the data will be later transferred to Mark5A at Haystack Observatory. - The synch time for the VLBA DiFX correlator using Mark5 is only a few seconds. Because of this, the 'early' start has been reduced to 10 seconds. - The fluxes use our most recent models. Purpose ======= This is the fourth of six coordinated astrometric/geodetic experiments in 2011 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: rdv88.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv88crd.br rdv88crd.fd rdv88crd.hn rdv88crd.kp rdv88crd.la rdv88crd.mk rdv88crd.nl rdv88crd.ov rdv88crd.pt rdv88crd.sc Summary file: rdv88.sksum Sked file: rdv88.skd Text file: rdv88.txt Vex file: rdv88.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2011/rdv88) Sked file: rdv88.skd Text file: rdv88.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: FORTLEZA, HARTRAO, NYALES20, TSUKUB32, and WETTZELL. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Ft=FORTLEZA Hh=HARTRAO Hn=HN-VLBA 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 Ft Hh Hn Kp La Mk Nl Ny Ov Pt Sc Ts Wz Avg % obs. time: 51 52 50 47 48 51 52 45 51 52 48 52 47 35 48 49 % cal. time: 3 3 2 2 3 4 4 4 3 3 4 4 3 4 3 3 % slew time: 23 22 30 41 21 24 23 25 22 15 26 23 22 16 8 23 % idle time: 22 22 17 9 26 20 21 25 22 29 21 20 27 44 39 25 total # scans: 300 302 215 211 277 324 307 319 291 265 341 309 276 329 254 288 # scans/hour : 13 13 9 9 12 14 13 13 12 11 14 13 12 14 11 12 Avg scan (sec): 146 148 201 191 151 136 145 122 152 169 122 146 148 92 164 148 # 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: 1685 1721 1631 1526 1604 1698 1718 1511 1696 1706 1616 1737 1568 1204 1588 1614 Total GB(M5): 1498 1530 1450 1357 1426 1510 1527 1343 1508 1517 1437 1544 1394 1070 1411 1435 # OF OBSERVATIONS BY BASELINE | Br Fd Ft Hh Hn Kp La Mk Nl Ny Ov Pt Sc Ts Wz StnTotal ------------------------------------------------------------------------------------- Br| 218 34 23 179 240 230 176 215 103 249 232 159 128 65 2251 Fd| 56 45 193 274 286 165 243 72 240 293 205 80 64 2434 Ft| 199 77 38 52 9 63 91 20 51 92 12 123 917 Hh| 65 27 41 0 52 80 9 40 81 13 115 790 Hn| 177 195 102 228 121 154 193 216 76 110 2086 Kp| 281 200 231 69 289 289 184 108 53 2460 La| 172 248 84 249 300 200 88 69 2495 Mk| 128 50 245 176 101 190 17 1731 Nl| 102 200 247 219 78 85 2339 Ny| 69 79 92 123 185 1320 Ov| 255 153 145 38 2315 Pt| 201 89 64 2509 Sc| 49 99 2051 Ts| 86 1265 Wz| 1173 Number of 2-station scans: 208 Number of 3-station scans: 146 Number of 4-station scans: 82 Number of 5-station scans: 28 Number of 6-station scans: 55 Number of 7-station scans: 37 Number of 8-station scans: 48 Number of 9-station scans: 46 Number of 10-station scans: 70 Number of 11-station scans: 46 Number of 12-station scans: 15 Number of 13-station scans: 13 Number of 14-station scans: 4 Number of 15-station scans: 0 Total # of scans, observations: 798 14068 SOURCE SELECTION ================ There are a total of 88 sources scheduled in this session. Among them, 29 sources are from the astrometric monitoring list, 40 are from the geodetic monitoring list, and 8 are previously observed sources that have only a few observations. There are also 11 new sources requested by Y. Kovalev. The requested sources are: 0449+125 04 52 42.61 +12 36 24.9 J0452+1236 0634+334 06 37 55.96 +33 22 05.2 J0637+3322 0747+104 07 50 32.90 +10 21 27.0 J0750+1021 0830+687 08 35 47.72 +68 35 10.9 J0835+6835 1126+109 11 28 45.53 +10 39 08.4 J1128+1039 1151+126 11 54 10.21 +12 25 09.1 J1154+1225 1508-111 15 10 44.39 -11 21 38.9 J1510-1121 1642-076 16 44 52.03 -07 43 43.7 J1644-0743 1734+065 17 36 28.56 +06 31 47.1 J1736+0631 1813+163 18 15 14.85 +16 23 46.7 J1815+1623 2131+145 21 33 37.38 +14 43 46.7 J2133+1443 SCHEDULING ALGORITHMS ===================== This schedule uses the "SRCEVN SQRT" mode of Sked. In the absence 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. The following tables list the setup for the VLBA stations, the geodetic stations with K5 back ends, and the geodetic stations with Mark IV back ends. These are the SAME frequencies used in all the standard RDV sessions. VLBA | TSUKUB32 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 FORTLEA, NYALES20, VLBA | HARTRAO, 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 L 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: ========================================= FORTLEZA, HARTRAO, Ny Alesund, Wettzell: These stations have Mark IV or Mark 5 racks. Please use the procedures generated by DRUDG. VCs 3 & 4 are used at X-band with IF 1. VCs 5 & 6 are used at X-band with IF 3. VCs 9, 10, 13, & 14 are used at S-band with IF B. 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. Tsukuba32: This stations use K4-2 VCs and a 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 the VCSX8 procedure after the comment about these converters being present, but not used. This will be corrected in a future DRUDG release. Please also set the attenuation and detector appropriately in the va=.. and vb=... commands. The tpicd commands in SX8M12A should be benign and do not need to be commented out unless they cause a problem. If you wish to record back-up channels, please add appropriate valo=..., va=... vblo=... and vb=... commands in the VCSX8 procedure. 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 the 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 cddisin.gsfc.nasa.gov/ivsincoming directory on vlbeer: aug11 directory on aspen: /astronomy/aug11/rdv88 or /home/archive/e2e/archive/operations/VLBA/observe/aug11/rdv88 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 on the VLBA-DiFX software correlator. Disks should be shipped (except Tsukuba) to Socorro as soon after the experiment as practical. The Tsukuba data should be e-transfered to Haystack as soon after the experiment as is practical. The VLBA needs to process the session at their correlator as soon as possible because of limited media. They prefer to have the data within one week of the observation, but in no case later than two weeks after the observation. So, we are asking all stations participating in the RDV sessions, to ship your media to the VLBA the same day the session ends or the next business day (just like the R1/R4 media is shipped). If you know that there is going to be a problem sending your media to the VLBA the same day the session ends or the next business day, please let us (ivscc@ivscc.gsfc.nasa.gov) know as soon as possible so that we, along with the VLBA, can determine the best course of action. If you have any questions or comments, please let us know.