RDV98 (Astrometric/Geodetic VLBA-98) 2013 APR 10 18:00 DOY 100 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 (HARTRAO, 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 two long scans on fairly strong sources with as many antennas as possible at the beginning and near the end of the schedule. All stations please try to be onsource and recording data for these scans. These scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Hh Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz 0059+581 13100-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0920+390 13100-180730| 300 300 300 300 300 300 300 300| 2229+695 13101-174336| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0641+392 13101-175229| 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 fluxes use our most recent models. Purpose ======= This is the second of six coordinated astrometric/geodetic sessions in 2013 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 60-70 sources from the pool of geodetic, astrometric, and monitoring sources. About 30-40 of these will remain the same from experiment to experiment and will be chosen to optimize the goals of the three groups. A number of poorly observed and/or new requested sources will 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: rdv98.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv98crd.br rdv98crd.fd rdv98crd.hn rdv98crd.kp rdv98crd.la rdv98crd.mk rdv98crd.nl rdv98crd.ov rdv98crd.pt rdv98crd.sc Summary file: rdv98.sksum Sked file: rdv98.skd Text file: rdv98.txt Vex file: rdv98.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2013/rdv98) Sked file: rdv98.skd Text file: rdv98.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: HARTRAO, MATERA, NYALES20, TSUKUB32, and WETTZELL. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Hh=HARTRAO 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 Wf=WESTFORD Wz=WETTZELL Br Fd Hh Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wf Wz Avg % obs. time: 48 50 44 45 50 50 43 44 48 42 48 50 45 28 0 33 42 % cal. time: 4 4 3 4 4 4 3 3 4 3 4 4 4 3 0 3 3 % slew time: 25 26 47 25 26 26 19 23 25 15 26 26 25 13 0 8 23 % idle time: 21 20 5 25 19 19 34 29 22 40 21 19 26 55 100 54 32 total # scans: 336 351 248 322 352 354 257 297 336 256 345 353 310 271 0 266 290 # scans/hour : 14 15 10 13 15 15 11 12 14 11 14 15 13 11 0 11 12 Avg scan (sec): 124 122 154 121 123 122 145 128 123 141 121 122 126 88 0 108 116 # data tracks: 16 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 16 Total GBytes: 1506 1545 1374 1400 1564 1555 1341 1364 1489 1295 1503 1546 1405 862 0 1033 1299 Total GB(M5): 1339 1373 1221 1244 1390 1382 1192 1213 1324 1151 1336 1374 1249 766 0 919 1154 Total GBytes (M5) recorded: 18471.2 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wf Wz StnTotal ------------------------------------------------------------------------------------------ Br| 231 14 213 243 247 25 212 242 118 267 246 167 154 0 36 2415 Fd| 33 226 321 327 24 205 279 63 271 331 232 84 0 30 2657 Hh| 57 21 31 228 0 41 107 10 29 74 65 0 207 917 Hn| 214 236 56 129 272 98 197 232 242 90 0 67 2329 Kp| 322 17 230 267 68 300 327 210 97 0 26 2663 La| 28 205 294 76 286 347 223 94 0 35 2751 Ma| 6 38 121 12 26 67 77 0 227 952 Mk| 165 73 246 208 116 138 0 20 1953 Nl| 90 246 289 236 96 0 46 2601 Ny| 84 75 58 144 0 134 1309 Ov| 288 174 130 0 22 2533 Pt| 222 93 0 34 2747 Sc| 53 0 73 2147 Ts| 0 80 1395 Wf| 0 0 Wz| 1037 Number of 2-station scans: 36 Number of 3-station scans: 183 Number of 4-station scans: 108 Number of 5-station scans: 78 Number of 6-station scans: 54 Number of 7-station scans: 47 Number of 8-station scans: 55 Number of 9-station scans: 62 Number of 10-station scans: 81 Number of 11-station scans: 43 Number of 12-station scans: 12 Number of 13-station scans: 7 Number of 14-station scans: 3 Number of 15-station scans: 0 Number of 16-station scans: 0 Total # of scans, observations: 769 15203 INTENSIVE BREAKS ================ WETTZELL is scheduled to participate in INT13-100, so they are not scheduled here from 18:15-19:45 on April 10. There also might 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 RDV98 for an ~1.5-2.0 hr period sometime during that window on DOY 100 or 101. 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 85 sources scheduled in this session. Among them, 25 sources are from the astrometric monitoring list, 30 are from the geodetic monitoring list, and 30 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 HARTRAO, MATERA, VLBA | NYALES20, 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: ========================================= HARTRAO, 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: apr13 directory on aspen: /astronomy/apr13/rdv98 or /home/archive/e2e/archive/operations/VLBA/observe/apr13/rdv98 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 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.