RDV95 (Astrometric/Geodetic VLBA-95) 2012 OCT 03 18:00 DOY 277 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 two long scans with most or all stations on fairly strong sources at the beginning of the schedule and two near the end and one in the middle. All stations please try to be onsource and recording data for the first of these scans. These scans are: ource Start DURATIONS name yyddd-hhmmss Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz 1357+769 12277-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0954+658 12277-180558| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0059+581 12278-040938| 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1300+580 12278-174712| 300 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 0014+813 12278-175349| 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 fifth 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: rdv95.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rdv95crd.br rdv95crd.fd rdv95crd.hn rdv95crd.kp rdv95crd.la rdv95crd.mk rdv95crd.nl rdv95crd.ov rdv95crd.pt rdv95crd.sc Summary file: rdv95.sksum Sked file: rdv95.skd Text file: rdv95.txt Vex file: rdv95.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2012/rdv95) Sked file: rdv95.skd Text file: rdv95.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: 49 50 49 43 51 51 43 44 48 40 49 51 44 27 36 42 % cal. time: 4 4 3 4 4 4 3 3 4 3 4 4 3 3 3 3 % slew time: 23 24 36 25 25 24 23 19 25 16 22 24 25 12 10 21 % idle time: 23 21 12 27 20 20 30 33 22 40 24 20 27 58 50 33 total # scans: 310 318 220 307 320 324 270 252 313 257 303 324 298 244 279 271 # scans/hour : 13 13 9 13 13 14 11 11 13 11 13 14 12 10 12 11 Avg scan (sec): 138 135 193 122 138 136 138 150 134 135 140 137 126 94 112 126 # 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: 1648 1663 1609 1457 1700 1703 1439 1452 1618 1345 1634 1714 1462 914 225 1411 Total GB(M5): 1465 1478 1430 1295 1511 1514 1279 1290 1438 1196 1452 1523 1300 813 088 1255 # OF OBSERVATIONS BY BASELINE | Br Fd Ft Hn Kp La Ma Mk Nl Ny Ov Pt Sc Ts Wz StnTotal ------------------------------------------------------------------------------------- Br| 219 46 202 233 240 44 187 235 103 240 238 164 133 47 2331 Fd| 79 205 281 285 48 170 253 67 235 288 215 77 47 2469 Ft| 88 55 63 169 29 69 97 37 60 115 19 158 1084 Hn| 192 213 87 117 244 102 175 206 242 83 90 2246 Kp| 291 34 197 251 66 269 299 186 90 33 2477 La| 46 179 273 78 259 313 204 88 47 2579 Ma| 18 60 163 27 42 94 88 244 1164 Mk| 154 63 212 185 109 125 28 1773 Nl| 87 227 267 224 89 63 2496 Ny| 69 72 77 137 165 1346 Ov| 263 161 109 34 2317 Pt| 202 86 43 2564 Sc| 51 91 2135 Ts| 100 1275 Wz| 1190 Number of 2-station scans: 21 Number of 3-station scans: 173 Number of 4-station scans: 132 Number of 5-station scans: 38 Number of 6-station scans: 53 Number of 7-station scans: 38 Number of 8-station scans: 47 Number of 9-station scans: 64 Number of 10-station scans: 69 Number of 11-station scans: 37 Number of 12-station scans: 11 Number of 13-station scans: 7 Number of 14-station scans: 6 Number of 15-station scans: 8 Total # of scans, observations: 704 14723 INTENSIVE BREAKS ================ Wettzell will drop out from approximately 18:15 until 19:45 on DOY 277 (Oct. 3) to run the daily UT1 intensive session. There may also 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 RDV95 for an ~1.5-2.0 hr period sometime during that window on DOY 277 or 278. 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 87 sources scheduled in this session. Among them, 30 sources are from the astrometric monitoring list, 30 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, 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: ========================================= 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: oct12 directory on aspen: /astronomy/oct12/rdv95 or /home/archive/e2e/archive/operations/VLBA/observe/oct12/rdv95 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.