RV112 (Astrometric/Geodetic VLBA-112) 2015 JULY 15 18:00 DOY 196 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. 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 4 non-VLBA stations scheduled (HARTRAO, KOKEE, NYALES20, 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 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 Kk Kp La Mk Nl Ny Ov Pt Sc Wz 0322+222 15196-180000| 300 300 300 300 300 300 300 300 300 300 300 300 | 1156+295 15196-180723| 300 300 300 300 300 300 300 300 300 300| 1156+295 15197-174347| 300 300 300 300 300 300 300 300 300 300 300| 0642+449 15197-175106| 300 300 300 300 300 300 300 300 300 300 300 300 300| Purpose ======= This is the fourth of six coordinated astrometric/geodetic sessions in 2015 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 orientation results ever produced. We will use these data to make the most precise measurements of UT1 and nutation. 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: rv112.skd On ftp.aoc.nrao.edu (aspen): VLBA Pointing files: 11211crd.br rv112crd.fd rv112crd.hn rv112crd.kp rv112crd.la rv112crd.mk rv112crd.nl rv112crd.ov rv112crd.pt rv112crd.sc Summary file: rv112.sksum Sked file: rv112.skd Text file: rv112.txt Vex file: rv112.vex At IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2015/rv112) Sked file: rv112.skd Text file: rv112.txt This experiment uses the 10 VLBA stations and 4 IVS stations. The IVS stations are: HARTRAO, KOKEE, NYALES20 and WETTZELL. Below is the sked summary: Key: Br=BR-VLBA Fd=FD-VLBA Hh=HARTRAO Hn=HN-VLBA Kk=KOKEE Kp=KP-VLBA La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Wz=WETTZELL Br Fd Hh Hn Kk Kp La Mk Nl Ny Ov Pt Sc Wz Avg % obs. time: 51 52 42 47 24 52 52 40 50 45 51 52 47 43 46 % cal. time: 4 4 3 3 3 4 4 3 4 3 4 4 3 3 4 % slew time: 25 24 44 21 15 24 23 21 22 14 25 23 22 8 23 % idle time: 20 19 10 27 57 20 20 35 22 36 19 20 26 44 27 total # scans: 328 339 240 302 216 339 340 285 328 272 344 342 302 256 302 # scans/hour : 14 14 10 13 9 14 14 12 14 11 14 14 13 11 13 Avg scan (sec): 133 132 151 135 97 132 131 120 133 144 127 131 134 146 131 # 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: 1.6 1.6 1.3 1.5 0.8 1.6 1.6 1.2 1.6 1.4 1.6 1.6 1.5 1.3 1.4 Total TB(M5): 1.4 1.4 1.2 1.3 0.7 1.4 1.4 1.1 1.4 1.3 1.4 1.4 1.3 1.2 1.3 # OF OBSERVATIONS BY BASELINE | Br Fd Hh Hn Kk Kp La Mk Nl Ny Ov Pt Sc Wz Total -------------------------------------------------------------------------------- Br| 259 26 198 133 265 267 201 240 84 265 272 176 46 2432 Fd| 51 222 104 314 322 181 280 55 262 325 219 38 2632 Hh| 109 0 36 48 0 73 186 15 42 116 213 915 Hn| 55 206 223 110 259 103 169 216 252 92 2214 Kk| 119 102 199 82 52 168 108 51 34 1207 Kp| 313 196 267 53 284 327 198 31 2609 La| 176 288 62 264 328 216 41 2650 Mk| 146 49 248 185 107 25 1823 Nl| 83 225 280 243 62 2528 Ny| 51 60 77 219 1134 Ov| 277 162 26 2416 Pt| 209 37 2666 Sc| 96 2122 Wz| 960 Number of 2-station scans: 0 Number of 3-station scans: 198 Number of 4-station scans: 65 Number of 5-station scans: 44 Number of 6-station scans: 53 Number of 7-station scans: 44 Number of 8-station scans: 59 Number of 9-station scans: 69 Number of 10-station scans: 76 Number of 11-station scans: 53 Number of 12-station scans: 7 Number of 13-station scans: 1 Number of 14-station scans: 0 Total number of scans: 669 Total number of obs: 14154 INTENSIVE BREAKS ================ There is an IVS INT01 Intensive session scheduled during RV112. Kokee and Wettzell will drop out from ~18:15 - 19:45 on DOY 196 for this Intensive. There will also be a USNO/NRAO UT1 Intensive session, scheduled to run at ~06:30 UTC (+/- 4 hrs), using Pietown and MK-VLBA on DOY 197, so these stations will drop out for about an hour. The exact time is not fixed, 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 84 sources scheduled in this session. Among them, 20 sources are from the astrometric monitoring list, 40 are from the geodetic monitoring list, and 24 are weaker sources whose positions we are trying to improve. 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 geodetic stations with DBBC, Mark IV, Mark 5, and VLBA5 back ends. VLBA | HARTRAO Chan Sky Tracks LO IF BBC | LO IF BBC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B2 725.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B2 845.75 6 5 S 2232.75 3, 5, 7, 9 3100 A 867.25| 2020.0 C1 212.75 9 6 S 2262.75 11,13,15,17 3100 A 837.25| 2020.0 C1 242.75 10 7 S 2352.75 19,21,23,25 3100 A 747.25| 2020.0 C1 332.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 2020.0 C1 352.75 14 VLBA | KOKEE Chan Sky Tracks LO IF BBC | LO IF VC BBC# 1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 7600.0 A 765.75 3 2 X 8445.75 10,12,14,16 7600 B 845.75| 7600.0 A 845.75 4 3 X 8805.75 18,20,22,24 9600 D 794.25| 8100.0 C 705.75 5 4 X 8925.75 26,28,30,32 9600 D 674.25| 8100.0 C 825.75 6 5 S 2232.75 3, 5, 7, 9 3100 A 867.25| 1500.0 B 732.75 9 6 S 2262.75 11,13,15,17 3100 A 837.25| 1500.0 B 762.75 10 7 S 2352.75 19,21,23,25 3100 A 747.25| 1500.0 B 852.75 13 8 S 2372.75 27,29,31,33 3100 A 727.25| 1500.0 B 872.75 14 VLBA | NYALES20, 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: ========================================= All non-VLBA stations: Please note that due to the frequency sequence, phase-cal will not be visible with a 10kHz viewing filter in the USB channels. If you have another means to verify phase-cal, please use it. If you have a Mark IV Decoder, please contact Ed.Himwich@nasa.gov if you would like advice on how to set it up to check phase-cal for this frequency sequence. HARTRAO: This station uses a DBBC rack. Please use the procedures generated by DRUDG. BBCs 3 & 4 are used at X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B, input 2. BBCs 9, 10, 13 & 14 are used for S-band with IF C, input 1. KOKEE: This station uses a VLBA5 rack. Please use the procedures generated by DRUDG. BBCs 3 & 4 are used at X-band with IF A. BBCs 5 & 6 are used at X-band with IF C. BBCs 9, 10, 13 & 14 are used at S-band with IF B. 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 2. 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: jul15 directory on aspen: /astronomy/jul15/rv112 or /home/archive/e2e/archive/operations/VLBA/observe/jul15/rv112 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 instead, where it will be copied and shipped to Socorro. These stations 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.