RDV93 (Astrometric/Geodetic VLBA-93) 2012 JUN 27 18:00 DOY 179 Notes prepared by David Gordon, Ed Himwich and John Gipson 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, MATERA, NYALES20, TSUKUB32, and WETTZELL). These stations should see the "Special operations notes for non-VLBA stations" section below for special instructions. To facilitate fringe-finding, there are several long scans on fairly strong sources at the beginning of the schedule and near the end. All stations please try to be onsource and recording data for the first of these scans. There are also several full-network scans in the middle of the session. These scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz 0602+673 12179-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0642+449 12179-180607| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 1030+415 12179-231420| 45 45 98 45 45 45 98 49 45 73 45 45 45 45 59| 0016+731 12180-065517| 90 89 151 83 98 84 151 107 84 103 96 95 77 56 111| 3C418 12180-082159| 45 45 102 45 45 45 102 82 45 70 45 45 45 61 80| 0016+731 12180-103147| 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 0016+731 12180-105937| 83 84 151 65 84 82 151 81 82 103 87 83 73 56 113| 0642+449 12180-174514| 300 300 300 300 300 300 300 300 300 300 300 300 300| 0602+673 12180-175114| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 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 third of six coordinated astrometric/geodetic sessions in 2012 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/astrometric VLBI programs of 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 and maintain 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: rdv93.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv93crd.br rdv93crd.fd rdv93crd.hn rdv93crd.kp rdv93crd.la rdv93crd.mk rdv93crd.nl rdv93crd.ov rdv93crd.pt rdv93crd.sc Summary file: rdv93.sksum Sked file: rdv93.skd Text file: rdv93.txt Vex file: rdv93.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2012/rdv93) Sked file: rdv93.skd Text file: rdv93.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: FORTLEZA, MATERA, NYALES20, TSUKUB32, and WETTZELL. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Ft=FORTLEZA Hn=HN-VLBA Kp=KP-VLBA La=LA-VLBA Ma=MATERA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Ts=TSUKUB32 Wz=WETTZELL Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz Avg % obs. time: 51 51 42 46 51 50 43 50 49 41 52 51 45 29 34 46 % cal. time: 4 4 3 4 4 4 4 4 4 4 4 4 4 4 4 4 % slew time: 24 23 42 23 24 23 27 23 23 18 24 24 23 16 13 24 % idle time: 20 22 12 26 21 23 25 22 24 36 20 21 27 51 48 27 total # scans: 328 319 258 313 318 311 321 314 306 323 317 316 308 330 347 315 # scans/hour : 14 13 11 13 13 13 13 13 13 13 13 13 13 14 14 13 Avg scan (sec): 133 137 142 128 139 139 116 137 137 110 140 139 127 75 83 124 # 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: 1688 1687 1410 1554 1703 1669 1452 1658 1622 1400 1716 1700 1524 1010 1168 1531 Total GB(M5): 1500 1499 1254 1381 1514 1484 1291 1474 1442 1244 1526 1511 1354 898 1038 1361 # OF OBSERVATIONS BY BASELINE | Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz StnTotal ------------------------------------------------------------------------------------- Br| 220 50 211 241 235 62 207 220 114 256 245 151 134 80 2426 Fd| 94 206 283 278 54 192 249 71 244 285 204 74 63 2517 Ft| 92 78 86 149 42 96 96 58 81 162 17 137 1238 Hn| 195 213 109 128 250 133 178 209 214 82 123 2343 Kp| 285 48 203 243 78 272 296 183 88 62 2555 La| 62 184 264 87 250 302 195 78 72 2591 Ma| 20 78 217 37 56 83 112 287 1374 Mk| 160 60 236 193 125 162 30 1942 Nl| 107 218 258 214 76 93 2526 Ny| 80 82 86 166 251 1628 Ov| 263 162 117 52 2423 Pt| 192 83 68 2613 Sc| 45 90 2106 Ts| 136 1370 Wz| 1544 Number of 2-station scans: 217 Number of 3-station scans: 139 Number of 4-station scans: 130 Number of 5-station scans: 42 Number of 6-station scans: 37 Number of 7-station scans: 57 Number of 8-station scans: 40 Number of 9-station scans: 50 Number of 10-station scans: 57 Number of 11-station scans: 58 Number of 12-station scans: 15 Number of 13-station scans: 16 Number of 14-station scans: 4 Number of 15-station scans: 7 Total # of scans, observations: 869 15598 INTENSIVE BREAKS ================ There is no INT01 UT1 session on June 27, so no intensive break is included in the schedule. However, there may be a USNO/NRAO UT1 intensive session using PIETOWN and MK-VLBA. The timing for this is somewhat flexible - sometime between 15:00 and 23:00 UTC. Therefore, PT and MK may be taken out of RDV93 for an ~1.5-2.0 hr period sometime during that window. We will leave the timing of this break to the discretion of the VLBA operators. From our standpoint, there is no particular period that is better or worse than another, and the loss of these two antennas for a short period should have only a minimal effect. SOURCE SELECTION ================ There are a total of 92 sources scheduled in this session. Among them, 30 sources are from the astrometric monitoring list, 35 are from the geodetic monitoring list, and 27 are previously observed sources that have only a few observations or were observed in only one session. 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 ============================== 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 FORTLEZA, NYALES20, VLBA | MATERA, 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, MATERA, NYALES20, and 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. TSUKUB32: This station uses K4-2 VCs and a K5 recorder. Please transfer data to Haystack in Mark IV format. 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: jun12 directory on aspen: /astronomy/jun12/rdv93 or /home/archive/e2e/archive/operations/VLBA/observe/jun12/rdv93 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 is practical. The Tsukuba data should be e-transfered to Haystack in Mark IV format as soon after the experiment as is practical. Ny Alesund may also use e-transfer and will need to coordinate this with Haystack if so. Socorro address for media shipping: VLBA Array Operations Center National Radio Astronomy Observatory Attn: Juan Cordova 1003 Lopezville Road Socorro, NM 87801 U.S.A. Phone: 575-835-7000 Shipping and VLBA contact information is also given at: https://science.nrao.edu/facilities/vlba/contact/shipping_information. Please use one of the recommended shipping companies (FedEx, UPS, DHL, TNT). 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. Therefore, please 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 and David.Gordon-1@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.