RDV86 (Astrometric/Geodetic VLBA-86) 2011 APR. 05 17:30 DOY 095 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 6 non-VLBA stations scheduled (FORTLEZA, HOBART12, HARTRAO, NYALES20, TSUKUB32, and WESTFORD). These stations should see the "Special operations notes for non-VLBA stations" section below for special instructions. FORTLEZA was added in tag-along mode, since they have not been observing recently and their participation is questionable. Tsukuba has been down due to the earthquake, but they will likely be back up for RDV86. The schedule begins and ends with several long scans which are designed to facilitate fringe finding at the VLBA correlator. Because of the widespread network, it is not possible to have all stations in a single scan, so there are separate fringe finder scans for Hobart12 and Hartrao. All stations please try to be onsource and recording data for these scans. There are also a few long scans in the middle with all of the northern hemisphere stations that could also be used as fringe finders. These scans are: Source Start DURATIONS name yyddd-hhmmss Br Fd Ft Hh Hn Hb Kp La Mk Nl Ny Ov Pt Sc Ts Wf 0059+581 11095-173000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 1057-797 11095-173000| 300 300 | 2008-159 11095-173745| 300 300 300 300 300 300 300 300 300 300 | 0642+449 11095-174456| 300 300 300 300 300 300 300 300 300 300 300| 0716+714 11096-004238| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1357+769 11096-033219| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 2229+695 11096-142930| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 2008-159 11096-171047| 300 300 300 300 300 300 300 300 300 300 | 0420-014 11096-171732| 300 300 300 300 300 300 300 300 300 300| 0059+581 11096-172433| 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, 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 second 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: rdv86.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv86crd.br rdv86crd.fd rdv86crd.hn rdv86crd.kp rdv86crd.la rdv86crd.mk rdv86crd.nl rdv86crd.ov rdv86crd.pt rdv86crd.sc Summary file: rdv86.sksum Sked file: rdv86.skd Text file: rdv86.txt Vex file: rdv86.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2011/rdv86) Sked file: rdv86.skd Text file: rdv86.txt This experiment uses the 10 VLBA stations and 6 IVS stations. The IVS stations are: FORTLEZA, HARTRAO, HOBART12, NYALES20, TSUKUB32, and WESTFORD. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Ft=FORTLEZA Hh=HARTRAO Hn=HN-VLBA Hb=HOBART12 Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Ts=TSUKUB32 Wf=WESTFORD Br Fd Ft Hh Hn Hb Kp La Mk Nl Ny Ov Pt Sc Ts Wf Avg % obs. time: 51 54 23 38 49 36 54 54 49 52 55 51 54 48 40 55 48 % cal. time: 3 4 2 2 4 3 3 3 4 4 3 3 4 3 4 3 3 % slew time: 23 23 20 42 24 8 23 23 26 24 15 23 23 25 17 14 23 % idle time: 21 19 54 17 23 52 19 18 21 20 26 21 18 22 38 27 26 total # scans: 295 303 138 192 304 246 302 301 304 307 247 295 304 297 340 249 276 # scans/hour : 12 13 6 8 13 10 13 13 13 13 10 12 13 12 14 10 12 Avg scan (sec): 150 153 143 171 138 126 154 156 140 147 191 150 154 140 103 192 150 # 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: 1703 1783 762 1253 1622 1205 1779 1796 1639 1733 1789 1695 1795 1602 1382 1812 1584 Total GB(M5): 1514 1585 678 1114 1442 1071 1581 1596 1457 1540 1590 1507 1595 1424 1228 1611 1408 # OF OBSERVATIONS BY BASELINE | Br Fd Ft Hh Hn Hb Kp La Mk Nl Ny Ov Pt Sc Ts Wf StnTotal ------------------------------------------------------------------------------------------ Br| 232 67 39 236 13 241 242 157 246 138 245 243 214 108 163 2584 Fd| 82 64 266 10 282 289 143 281 118 239 291 259 72 192 2820 Ft| 80 92 4 74 84 24 86 90 57 86 95 17 101 1039 Hh| 76 51 49 63 0 69 90 25 61 82 39 89 877 Hn| 2 248 269 124 287 137 222 266 266 78 210 2779 Hb| 15 9 116 6 22 28 10 4 169 4 463 Kp| 276 159 267 109 258 282 241 80 177 2758 La| 139 285 123 242 297 260 78 195 2851 Mk| 132 70 179 143 116 169 82 1753 Nl| 133 236 283 268 81 205 2865 Ny| 104 124 120 122 160 1660 Ov| 246 206 99 153 2539 Pt| 257 78 193 2860 Sc| 60 197 2645 Ts| 61 1311 Wf| 2182 Number of 2-station scans: 195 Number of 3-station scans: 150 Number of 4-station scans: 52 Number of 5-station scans: 27 Number of 6-station scans: 16 Number of 7-station scans: 18 Number of 8-station scans: 20 Number of 9-station scans: 39 Number of 10-station scans: 61 Number of 11-station scans: 60 Number of 12-station scans: 54 Number of 13-station scans: 40 Number of 14-station scans: 5 Number of 15-station scans: 0 Number of 16-station scans: 0 Total # of scans, observations: 737 16993 SOURCE SELECTION ================ There are a total of 90 sources scheduled in this session. Among them, 30 sources are from the astrometric monitoring list, 44 are from the geodetic monitoring list, and 15 are previously observed sources that have only a few observations. There is also 1 new source requested by L. Petrov which was too close to the sun to be observed in the previous RDV. The requested source is: 2227-210 22 29 48.20 -20 49 26.0 J2229-2049 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, WESTFORD 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 VLBA | HOBART12 (to be verified) 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, Westford: These stations have Mark IV 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: These 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. HOBART12 This station has a DBBC rack and Mark 5B recorder. You should use the procedures generated by DRUDG for rack type "none" and recorder type "Mark5B". Since we don't understand the configuration of the DBBC, you will have to determine yourselves how to configure it to record the observed sky frequencies and mode. You will also have to determine the correct Mark 5B bit-mask. Please note you must preserve the specified channel order in the recording. However there can be unused input channels that aren't recorded intermingled with the real channels as long as they are deslected from recording by the bit-mask. Please contact Ed (Ed.Himwich@nasa.gov) if you have any questions about what needs to be done. The frequencies and set-up given for this station in previous section are provisional. Please contact Ed to confirm or amend the details depending on which is appropriate. 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 cddisin.gsfc.nasa.gov/ivsincoming directory on vlbeer: apr11 directory on aspen: /astronomy/apr11/rdv86 or /home/archive/e2e/archive/operations/VLBA/observe/apr11/rdv86 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.