RV101 (Astrometric/Geodetic VLBA-101) 2013 SEPT 11 18:00 DOY 254 Notes prepared by David Gordon, Ed Himwich and John Gipson NVI/GSFC Important Note: =============== Beginning with number 100, the 'RDV' sessions are now called the 'RV' sessions. This was necessary because the VLBA schedules only allow for 5-character project codes, so rdv101 had to be changed to rv101. 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 4 non-VLBA stations scheduled (MATERA, NYALES20, ONSALA60 and WESTFORD). 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 with all antennas at the beginning, in the middle, 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 Hn Kp La Ma Mk Nl Ny On Ov Pt Sc Wf 1803+784 13254-180000| 300 300 300 300 300 300 300 300 300 300 300 300 300 300| 2229+695 13255-004812| 200 200 200 200 200 200 200 200 200 200 200 200 200 200| 1803+784 13255-174954| 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. - The fluxes use our most recent models. Purpose ======= This is the fifth 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: rv101.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: rv101crd.br rv101crd.fd rv101crd.hn rv101crd.kp rv101crd.la rv101crd.mk rv101crd.nl rv101crd.ov rv101crd.pt rv101crd.sc Summary file: rv101.sksum Sked file: rv101.skd Text file: rv101.txt Vex file: rv101.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2013/rv101) Sked file: rv101.skd Text file: rv101.txt Vex file: rv101.vex This experiment uses the 10 VLBA stations and 4 IVS stations. The IVS stations are: MATERA, NYALES20, ONSALA60 and WESTFORD. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Hn=HN-VLBA Kp=KP-VLBA La=LA-VLBA Ma=MATERA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 On=ONSALA60 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Wf=WESTFORD Br Fd Hn Kp La Ma Mk Nl Ny On Ov Pt Sc Wf Avg % obs. time: 54 59 50 59 59 44 51 56 42 48 57 59 53 43 52 % cal. time: 4 4 4 4 4 4 3 4 4 4 4 4 4 4 4 % slew time: 22 22 25 22 23 31 23 23 21 26 23 23 24 17 24 % idle time: 19 14 21 14 14 20 21 17 32 22 16 14 18 35 20 total # scans: 314 326 331 322 324 367 293 331 343 378 319 323 311 319 328 # scans/hour : 13 14 14 13 14 15 12 14 14 16 13 13 13 13 14 Avg scan (sec): 148 156 130 159 156 104 151 145 106 109 155 157 147 117 138 # data tracks: 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 Total TBytes: 1.7 1.8 1.6 1.8 1.8 1.4 1.6 1.7 1.3 1.5 1.8 1.8 1.6 1.3 1.6 Total TB(M5): 1.5 1.6 1.4 1.6 1.6 1.2 1.4 1.5 1.2 1.3 1.6 1.6 1.5 1.2 1.4 # OF OBSERVATIONS BY BASELINE | Br Fd Hn Kp La Ma Mk Nl Ny On Ov Pt Sc Wf Total -------------------------------------------------------------------------------- Br| 201 189 215 217 43 206 219 80 47 234 217 157 118 2143 Fd| 192 295 301 39 196 243 46 40 248 301 214 125 2441 Hn| 180 195 87 118 253 90 90 162 193 235 204 2188 Kp| 300 32 214 232 41 34 271 307 193 116 2430 La| 37 204 250 45 39 266 316 203 126 2499 Ma| 21 58 259 353 25 37 65 140 1196 Mk| 153 60 27 233 205 119 71 1827 Nl| 70 59 212 247 232 168 2396 Ny| 280 51 45 58 128 1253 On| 29 38 62 143 1241 Ov| 268 168 104 2271 Pt| 201 125 2500 Sc| 174 2081 Wf| 1742 Number of 2-station scans: 157 Number of 3-station scans: 238 Number of 4-station scans: 112 Number of 5-station scans: 47 Number of 6-station scans: 54 Number of 7-station scans: 49 Number of 8-station scans: 48 Number of 9-station scans: 40 Number of 10-station scans: 70 Number of 11-station scans: 31 Number of 12-station scans: 13 Number of 13-station scans: 12 Number of 14-station scans: 9 Total # of scans, observations: 880 14104 INTENSIVE BREAKS ================ There is no INT01 Intensive session scheduled during RV101. But there will be a USNO/NRAO UT1 Intensive session, scheduled to run at ~06:30 UTC (+/- 4 hrs), using Pietown and MK-VLBA. Therefore, Pietown and MK-VLBA will be taken out for about an hour. The exact time is unkonwn, 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 90 sources scheduled in this session. Among them, 25 sources are from the astrometric monitoring list, 35 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 and the Mark4 geodetic stations with Mark IV back ends. These are the SAME frequencies used in all the standard RDV/RV sessions. ONSALA60, VLBA | NYALES20, 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 | MATERA 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 11 H 8 S 2372.99 27,29,31,33 2900 A 527.01| 2020.0 2 352.99 12 H Special operations for non-VLBA stations: ========================================= NYALES20, ONSALA60 and WESTFORD: 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. MATERA: This station has 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, 11 & 12 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. 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: sep13 directory on aspen: /astronomy/sep13/rv101 or /home/archive/e2e/archive/operations/VLBA/observe/sep13/rv101 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. Ny Alesund may use e-transfer 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.