RV106 (Astrometric/Geodetic VLBA-106) 2014 SEP 03 18:00 DOY 246 Notes prepared by David Gordon, Ed Himwich and John Gipson NVI/GSFC Special notes for this experiment ================================= This session will use the RDBE/DDC/Mark5C system at the VLBA sites, as in the previous RV session. And it will again use the new RDV frequency sequence. The X-band frequencies are: 8365.75, 8445.75, 8805.75, and 8925.75 MHz, and now span 560 MHz. The new S-band frequencies are: 2232.75, 2262.75, 2352.75, and 2372.75 MHz. The ending in .75 MHz is necessary at the VLBA stations. Therefore it will not be possible to monitor phase cals using the 10 kHz filters. Ed Himwich may provide alternate instructions for monitoring phase cals. This session will record 8 8-MHz bandwidth channels using 2-bit sampling, as in previous RDV's. The bit rate will be 256 Mbits/sec. The data will be correlated at the VLBA using the VLBA DiFX software correlator. There are 5 non-VLBA stations scheduled (HARTRAO, MATERA, NYALES20, WESTFORD, 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 some long scans on fairly strong sources with most antennas at the beginning, in the middle, and at 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 Wf Wz 1803+784 14246-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 1406-076 14246-180642| 300 300 300 300 300 300 300 300 300 300| 1803+784 14247-023159| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1803+784 14247-174506| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 1406-076 14247-175322| 300 300 300 300 300 300 300 300 300 300 300| Purpose ======= This is the fourth of six coordinated astrometric/geodetic sessions in 2014 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 20-30 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: rv106.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rv106crd.br rv106crd.fd rv106crd.hn rv106crd.kp rv106crd.la rv106crd.mk rv106crd.nl rv106crd.ov rv106crd.pt rv106crd.sc Summary file: rv106.sksum Sked file: rv106.skd Text file: rv106.txt Vex file: rv106.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2014/rv106) Sked file: rv106.skd Text file: rv106.txt This experiment uses the 10 VLBA stations and 5 IVS stations. The IVS stations are: HARTRAO, MATERA, NYALES20, WESTFORD 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 Wf=WESTFORD Wz=WETTZELL Br Fd Hh Hn Kp La Ma Mk Nl Ny Ov Pt Sc Wf Wz Avg % obs. time: 50 54 43 45 55 55 46 44 51 44 52 55 47 44 35 48 % cal. time: 4 4 3 4 4 4 3 3 4 3 4 4 3 3 3 3 % slew time: 23 24 42 24 24 24 21 17 24 14 23 24 22 16 9 23 % idle time: 23 16 11 27 16 16 29 35 21 38 21 16 26 37 53 26 total # scans: 315 323 229 306 326 324 259 254 321 250 312 328 281 271 264 290 # scans/hour : 13 13 10 13 14 14 11 11 13 10 13 14 12 11 11 12 Avg scan (sec): 137 145 163 126 145 146 154 149 137 150 143 144 146 138 113 141 # 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 TBytes: 1.5 1.7 1.3 1.4 1.7 1.7 1.4 1.4 1.6 1.4 1.6 1.7 1.5 1.4 1.1 1.5 Total TB(M5): 1.4 1.5 1.2 1.2 1.5 1.5 1.3 1.2 1.4 1.2 1.4 1.5 1.3 1.2 1.0 1.3 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Kp La Ma Mk Nl Ny Ov Pt Sc Wf Wz Total ------------------------------------------------------------------------------------- Br| 248 23 210 253 257 37 208 257 103 260 258 176 137 44 2471 Fd| 38 214 302 309 42 204 276 74 274 315 209 144 42 2691 Hh| 75 25 36 222 0 47 130 13 33 80 104 211 1037 Hn| 199 219 84 125 253 112 177 213 233 217 88 2419 Kp| 303 30 222 260 71 293 311 192 130 29 2620 La| 41 202 280 77 273 317 211 146 41 2712 Ma| 8 54 166 20 38 86 125 242 1195 Mk| 170 49 237 211 113 71 14 1834 Nl| 96 237 274 226 175 57 2662 Ny| 70 78 75 143 164 1408 Ov| 281 167 108 20 2430 Pt| 207 141 38 2715 Sc| 177 85 2237 Wf| 123 1941 Wz| 1198 Number of 2-station scans: 0 Number of 3-station scans: 108 Number of 4-station scans: 121 Number of 5-station scans: 51 Number of 6-station scans: 49 Number of 7-station scans: 41 Number of 8-station scans: 61 Number of 9-station scans: 39 Number of 10-station scans: 76 Number of 11-station scans: 54 Number of 12-station scans: 20 Number of 13-station scans: 8 Number of 14-station scans: 13 Number of 15-station scans: 0 Total number of scans: 641 Total number of obs: 15785 INTENSIVE BREAKS ================ There is an IVS INT01 Intensive session scheduled during RV106, so WETTZELL will drop out from ~18:15-19:45. There will also be a USNO/NRAO UT1 Intensive session, scheduled to run at ~06:30 UTC (+/- 4 hrs), using Pietown and MK-VLBA, so these stations will drop out for about an hour. The exact time is unknown, so it is not scheduled in, but the loss of these two antennas for a short period should have only a minimal effect. SOURCE SELECTION ================ There are a total of 88 sources scheduled in this session. Among them, 20 sources are from the astrometric monitoring list, 41 are from the geodetic monitoring list, and 27 are previously observed Gaia category 4 sources or other sources that have only a few observations. 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 560 MHz at X-band and 140 MHz at S-band using 4 channels in each band. At the VLBA, the X-band uses two LO's in order to fit in the VLBA 512 MHz passband. At the Mark4 stations, the X-band 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 and the Mark4 geodetic stations with Mark IV back ends. MATERA, HARTRAO, NYALES20, VLBA | WESTFORD, WETTZELL Chan Sky Tracks LO IF BBC | LO IF VC VC# Patch 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 1 285.75 3 H 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 1 365.75 4 H 3 X 8805.75 18,20,22,24 9600 D 794.25| 8580.1 3 225.65 5 3(H) 4 X 8925.75 26,28,30,32 9600 D 674.25| 8580.1 3 345.65 6 3(H) 5 S 2232.75 3, 5, 7, 9 3100 A 867.25| 2020.0 2 212.75 9 L 6 S 2262.75 11,13,15,17 3100 A 837.25| 2020.0 2 242.75 10 H 7 S 2352.75 19,21,23,25 3100 A 747.25| 2020.0 2 332.75 13 H 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 2 352.75 14 H Special operations for non-VLBA stations: ========================================= MATERA, HARTRAO, NYALES20, WESTFORD 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. 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: sep14 directory on aspen: /astronomy/sep14/rv106 or /home/archive/e2e/archive/operations/VLBA/observe/sep14/rv106 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. Some stations may E-transfer their data to Haystack in Mark IV format instead and will need to coordinate this with Haystack Observatory. 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.