RDV12 (Astrometric/Geodetic VLBA-08) 1998 December 21 Notes prepared by Nancy Vandenberg, NVI/GSFC Schedule name: rdv12.skd Pointing files: rdv12crd.br, rdv12crd.fd, rdv12crd.hn, rdv12crd.kp, rdv12crd.la, rdv12crd.mk, rdv12crd.nl, rdv12crd.ov, rdv12crd.pt, rdv12crd.sc on aspen in directory /home/aspen6/astronomy/dec98/rdv12 PCFS file: rdv12.skd on cddisa in directory dec98 or via http://lupus.gsfc.nasa.gov/sess/1998/sesshtml/rdv12.html Nominal Start: 16:00 U.T. on December 21 (day 355) first observation at 15:35 U.T. on 1803+784 for Br-Fd-Gc-Hn Kp-La-Nl-Ov-Pt-Sc-Wf first observation at 16:05 U.T. on NRAO512 for Kk-Mc-Mk-Ny-On first observation at 16:37 U.T. on OQ208 for Gn Duration: 24 hours + 1 hour extra for Gc-Gg-Wf-Br-Fd-Hn-Kp-La-Nl-Ov-Pt-Sc Nominal Stop: 16:00 U.T. on December 22 (day 356) last observation at 15:57 U.T. on 1706-174 For Gn last observation at 15:58 U.T. on 0952+179 for Kk-Mk last observation at 15:59 U.T. on 0804+499 for Mc-Ny-On last observation at 16:13 U.T. on 1739+522 for Br-Fd-Gc-Hn- Kp-La-Nl-Gg-Ov-Pt-Sc-Wf Correlator: VLBA at Socorro Summary file for correlator: rdv12.sksum on aspen Stations: 18 Station Codes # of tapes # of obs Occupation Code Brewster B Br 2.3 (TT) 281 76149901 Fort Davis D Fd 2.3 (TT) 293 76139801 Gilcreek A Al 2.3 (TT) 250 40476601 Hancock H Hn 2.3 (TT) 269 76185001 Kokee K Kk 2.2 (TT) 251 72983001 Kitt Peak L Kp 2.3 (TT) 289 76109401 Los Alamos M La 2.3 (TT) 296 76119601 Medicina C Mc 3.1 (TT) 205 72308801 Mauna Kea N Mk 2.1 (TT) 254 76175501 North Liberty O Nl 2.3 (TT) 296 76129701 Green Bank 20m P Gn 2.1 (TT) 280 72484701 Ny Alesund Q Ny 2.1 (TT) 221 73313301 Onsala T On 2.1 (TT) 215 72137701 GGAO (MV3) Z Gg 2.3 (TT) 248 71085301 Owens Valley R Ov 2.2 (TT) 274 76165401 Pie Town S Pt 2.3 (TT) 294 72348601 St. Croix E Sc 2.2 (TT) 256 76159001 Westford F Wf 2.2 (TT) 274 72097301 Special notes on tape usage: - This experiment uses THIN TAPES ONLY at all stations. - The VLBA stations will use dynamic tape allocation for this experiment. - Gn will record the intensive and then join the experiment at 1640 UT. They will change tape at 0330 UT and then run unattended for the night shift. - Most VLBA stations record the two initial MV3 fringe finding scans along with Fairbanks and Westford. These stations also record two final long scans. Purpose ======= This is the last of six bi-monthly coordinated astrometric/geodetic experiments in 1998 that use the full 10-station VLBA plus the 8 geodetic stations currently capable of recording VLBA modes. This year's series is a continuation of the highly successful series 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 will perform repeated 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 small numbers of sources. While the quality of these results will be high, the observing and data reduction overhead required will be minimal because 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 out of the pool of ~400 Northern Hemisphere ICRF 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. Schedule ======== This is a new schedule generated by Marshall Eubanks using the 9706 version of the NASA sked program which handles continuous tape motion. All stations use thin tapes. "Requested" Sources in RD-V12 : 1026-084 10 28 38.82 -08 44 38.6 2000.0 0.0 test-new-Gurvits | 0013-005 | 0055+300 NGC0315 | 0248+430 | 0400+258 N | 0400-319 | 0536+145 | 0646-306 Y | 0742+103 | 0831+557 | 0952+179 | 1111+149 | 1253-055 3C279 | 1352-104 | 1430+365 NGC5675 | 1519-273 | 1555-140 | 1657-261 | 1706-174 N | 1738+499 | 1932+106 | 2008-159 | 2254+024 Y | 2255-282 | 2320-035 | 2351-154 With this session we continue rotating through the large list of candidate ICRF sources. The method was as follows: - Remove sources from the core list of 80 sources used last year. - Add up to 20 sources from the list of candidates that already have some NEOS or VLBA data available (rotating sources). - Add 3 sources from the list of candidates that have never been observed with the VLBA (new sources). The same criteria were used for generating this schedule as were used during the first year of these sessions. The criteria for sources to be mapped are a minimum of 3 scans and 135 observations. These criteria are relaxed for sources below -25 degrees declination. Most of the sources in this schedule meet the mapping criteria. The schedule was made using a combination of automatic selection plus manual scheduling to improve the coverage of the sources. Automatically scheduled scans were selected first on their improvement of sky coverage in the previous 1 hour, and then the best 60% were evaluated for the minor options: minimize idle time, minimize slewing time, and maximize the number of observations. An individual source was not observed more often than every 90 minutes. An early start of 30 seconds was used for the first scan on a tape pass. The minimum scan length was 40 seconds. Due to its low sensitivity, MV3 was not included directly into the schedule because the necessarily longer scan lengths would have compromised the experiment results. Instead, after the schedule was made, MV3 was tagged along to the schedule. In the tagalong mode, MV3 observes with the longest scan duration of all the stations participating in each scan, to maximize SNR. MV3 will make fringes on about 2/3 of the observations in which it participates. This amount of data will allow a good determination of MV3's position in the reference frame. Recording Mode and Frequencies: same as previous experiments ============================================================ The data will be recorded using 8 channels, 1:4 fan-out, 16 MHz sample rate, 1-bit sampling. This recording mode is designated 128-8-1. The correlator gets a speed-up factor of 2. The frequency sequence covers 490 MHz in 8 channels. 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 are available when observing with the VLBA stations, a wider spanned bandwidth is not advisable. With the 1:4 fanout at 16 MHz sample rate, all 32 tracks are recorded in one pass, so there will be 14 passes on a tape. These tables list the setup for the VLBA stations, the geodetic stations with VLBA back ends, and the geodetic stations with Mark IV back ends. These are the SAME frequencies used in all the standard RDV sessions. Geodetic stations: please read the special procedures in the next section! VLBA | Fairbanks | Kokee, GB Chan Sky Tracks LO IF BBC | LO IF BBC | LO IF BBC 1 X 8405.99 2, 4, 6, 8 7900 B 505.99| 7600.1 B 805.89| 7600 B 805.99 2 X 8475.99 10,12,14,16 7900 B 575.99| 7600.1 B 875.89| 7600 B 875.99 3 X 8790.99 18,20,22,24 7900 B 890.99| 8080.0 C 710.99| 8100 C 690.99 4 X 8895.99 26,28,30,32 7900 B 995.99| 8080.0 C 815.99| 8100 C 795.99 5 S 2220.99 3, 5, 7, 9 2900 A 679.01| 1540.1 A 680.89| 1500 A 720.99 6 S 2240.99 11,13,15,17 2900 A 659.01| 1540.1 A 700.89| 1500 A 740.99 7 S 2330.99 19,21,23,25 2900 A 569.01| 1540.1 A 790.89| 1500 A 830.99 8 S 2360.99 27,29,31,33 2900 A 539.01| 1540.1 A 820.89| 1500 A 860.99 Onsala, Medicina, VLBA | Westford, MV3, Ny Alesund 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 L 4 X 8895.99 26,28,30,32 7900 B 995.99| 8580.1 3 315.89 6 H 5 S 2220.99 3, 5, 7, 9 2900 A 679.01| 2020.0 2 200.99 9 L 6 S 2240.99 11,13,15,17 2900 A 659.01| 2020.0 2 220.99 10 L 7 S 2330.99 19,21,23,25 2900 A 569.01| 2020.0 2 310.99 13 H 8 S 2360.99 27,29,31,33 2900 A 539.01| 2020.0 2 340.99 14 H Procedures ========== With continuous tape motion, the tape starts moving and recording at the beginning of the first scan of a pass. The tape runs and records continuously thereafter to the end of the tape (EOT or BOT). A parity check is done after the tape reaches this point. The tape starts moving in the opposite direction at the early start time (30 seconds) before the next scan. There will be a variable length of time between tape passes. For the VLBA stations, there will normally be a long enough time gap between passes for playback. Special procedures for non-VLBA stations ======================================== The tape motion in this experiment will be different from normal start&stop schedules. Please read this section carefully so that you know what to expect. At the time the antenna gets on source, you should see the "Data start" comment from the SNAP schedule. This is the signal that the VLBA correlator will use to determine when to start correlating this scan. At the time the antenna begins slewing to the next source, you will see the "Data stop" comment from the schedule. This is the signal the correlator will use to stop correlating that scan. There will be no "et" command at the end of a scan. The DRUDG listing has an extra column that lists the time that the tape will stop. Note the "Start Tape" and "Stop Tape" columns list times only when the tape will start or stop, otherwise the time is blanked out because the tape is moving. For each scan, the "Start Data" column will be the time when the antenna is expected to be on source. The "Stop Data" column is the time when the antenna starts slewing to the next source. After the setup procedure, the tape is started at the beginning of each pass and will continue to move, at record speed, until it reaches the end of the pass. There are no fast tape motions in this schedule. The tape is continuously recording from the initial "st" command at the start of the pass. There are no other "st" commands during a pass and there are no other setup procedures called. If you have to re-start the schedule for a problem or emergency, you will be able to do it either 1) at the beginning of a pass or 2) in the middle of a pass by entering the setup and start tape commands manually. The problem is that the heads cannot be positioned reliably when the tape is moving if there is recorded data on the tape. If the tape is moving the reproduce power level can cause cross-talk with the head positioner and give false indications of position. At the end of each pass a parity check is done. You will need procedures named "check2m1, check2m2" or "check2v1, check2v2". If you have not already done so for the first two sessions, please create these procedures as a copy of "check2c1, check2c2" and change the tracks to be "v0,v1,v2,v3". Check and adjust the timing of this procedure and then make sure it can complete in the 70 seconds that the schedule allows. If it cannot be completed, you could check the odd tracks in one direction and the even tracks in the other. Special procedures for Onsala, Medicina, Westford, MV3, Ny Alesund ================================================================== Onsala, Medicina, Westford, MV3, and Ny Alesund have Mark IV formatters. Use the procedures generated by DRUDG. These should be the same as the ones used in previous RDV sessions. This is a non-standard setup. There are 8 video converters used: 3, 4, 5, 6, 9, 10, 13, and 14. These were selected so that you will NOT have to change the standard geodetic IF patching. The 6 unused VCs 1, 2, 7, 8, 11, and 12 should be set to frequencies which do not occur in any of the passbands. Any value in the 100-200 MHz range is OK. The Mark IV formatters currently have no barrel roll capability, so please verify that your FORM command has no specification for barrel roll. The IF3 command in the procedure IFDSX assumes that VC3 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. If you have questions about the wiring, please contact Brian Corey at Haystack. Special procedures for Fairbanks, Kokee, Green Bank =================================================== Fairbanks, Kokee, and Green Bank have VLBA back ends. Use the procedures generated by DRUDG. These should be the same as the ones used in previous RDV sessions. You must swap your IF inputs so that BBCs 1-8 have the inputs shown in the table above. The unused BBCs 9-14 should be set to frequencies which do not occur in any of the passbands. Any value in the range 500-600 MHz is OK. The formatter should be set up to use barrel roll. Please verify that you are using the same barrel roll as you used in previous sessions correlated at the VLBA. 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. Make and check out parity check procedures. 2. Make .snp file and listings using DRUDG options 3 or 31 and 5. 3. Set up your system to monitor the clocks with the "gps-fmout" or "fmout-gps" commands. If you have questions or problems, please contact Ed Himwich as soon as possible. 4. Send a "ready" message an hour or so before the experiment to the ops mail list. Copy analysts@nrao.edu and pperley@nrao.edu on the message. 5. Send a "start" message soon after you have started recording. Copy analysts@nrao.edu and pperley@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 and pperley@nrao.edu on the message. 8. Transfer your log files to your normal log file data center. The directories for three possible servers are listed below: directory on cddisa: dec98 directory on vlbeer: dec98 directory on aspen: /home/aspen6/astronomy/dec98/rdv12 Correlation =========== This experiment will be correlated at the VLBA Correlator. Tapes should be shipped to Socorro as soon after the experiment as practical. Summary ======= The following listing is a summary of the observations in this schedule. SKED Summary from file ./rdv12.skd for experiment RDV12 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x x x x x I 6 113 1.8 0013-005Ix x x I 3 150 2.2 0014+813I x x x x x x xI 7 1003 6.6 0048-097I x x x x I 4 69 1.1 NGC0315 I x x x x I 4 409 4.3 0059+581I x x x x xx x x x x x x I 12 1261 9.3 0104-408I x x x x x x I 6 99 4.9 0119+115I x x x xI 4 280 3.5 0119+041I x x x I 3 213 2.9 0133+476Ix x x x x x x x I 8 700 5.9 0201+113I x I 1 78 1.0 0202+149I x x I 2 273 3.3 0208-512I x x I 2 2 .1 0229+131Ix x x x I 4 234 2.9 0234+285I x x x x x x x x I 8 583 6.2 NGC1052 I x x x x I 4 329 6.1 0248+430I x I 1 120 1.1 CTA26 I x x x x I 4 266 3.9 0400-319I x x x x I 4 183 5.5 0402-362I x x x I 3 101 4.8 3C120 Ix x x x x I 5 367 5.0 0454-234I x x I 2 79 1.8 0458-020I x I 1 1 .0 0528+134I x x x x I 4 291 3.6 0537-441I x x I 2 2 .1 0536+145I x x x x I 4 400 4.9 0552+398Ix x x x x x x I 7 832 7.8 0642+449I x x x x x x I 6 819 7.3 0646-306I x x x x I 4 112 3.1 0727-115I x x x x I 4 326 5.5 0742+103I x x x x x x I 6 505 6.5 0804+499I x x x x x x xx x x x I 11 795 6.6 0823+033I x x x x I 4 360 5.0 0831+557I x x x I 3 193 1.5 OJ287 I x x x x x x x x x I 9 759 8.7 0919-260I x x I 2 132 3.2 0920-397I x I 1 45 2.1 4C39.25 I x x x x x x x x I 8 834 8.0 0952+179I x x x I 3 147 1.7 0955+476I x x x x x x x x I 8 496 4.2 1022+194I x x x I 3 309 3.6 1026-084I x I 1 28 .5 1034-293I x x x I 3 149 4.1 1044+719I x xx x x x x x x xx x x x I 14 1314 8.9 1101+384I x x x x I 4 475 4.6 1111+149I x I 1 78 1.0 1124-186I x x I 2 106 2.2 1128+385I x x x I 3 363 3.5 1144-379I x I 1 55 2.2 1145-071I x x x x x I 5 275 4.6 1156+295I x x x x x I 5 428 4.6 3C274 I x x x x x x x I 7 439 5.5 3C279 I x x x x x I 5 434 7.0 1308+326I x x x x x x xx I 8 729 7.5 1313-333I x x x x I 4 140 4.5 1334-127I x x x I 3 112 1.9 1352-104I x x x I 3 180 3.2 1357+769I x x x x x x x x I 8 893 5.9 OQ208 I x x x x x x x x I 8 671 7.1 1424-418I x x I 2 37 2.7 NGC5675 I I 0 0 .0 1451-375I x I 1 1 .0 1514-241I x x x x x I 5 204 4.8 1519-273I x x x I 3 137 3.6 1555-140I x I 1 66 1.2 1606+106I x x x x x x x I 7 549 7.0 1611+343I x x x x x I 5 547 5.5 1622-253I x x I 2 92 2.2 NRAO512 I x x x x x x x x I 9 862 8.1 1657-261I x x x x I 4 214 5.1 1706-174I x x I 2 94 1.9 1738+499I x x x I 3 266 2.2 1739+522Ix xx x x xxx x x x I 11 991 8.0 1741-038I x x x x x x I 6 396 6.0 1745+624I I 0 0 .0 1749+096I x x x x x x I 6 337 4.3 1803+784I x x x x x x x x x x x x I 12 1330 8.7 1815-553I x I 1 1 .2 1908-201I x x x x x x I 6 253 5.4 1921-293I x x x x I 4 116 3.1 1932+106I x x x x x I 5 391 5.0 1954-388I x x I 2 29 1.3 2008-159I x x x x I 4 238 4.7 2052-474I x x I 2 2 .1 2145+067I x x x x x x xI 7 534 7.1 VR422201I xx x x x x x x xI 9 964 8.8 2234+282I x x x x x x I 6 437 4.7 2243-123I x x x x x x x I 7 244 4.1 2254+024I x x x I 3 213 3.0 2255-282I x x x x x I 5 202 5.2 2320-035I x x I 2 132 2.0 2351-154Ix x x I 3 158 3.1 Total scans, obs: 417 31176 Average number of obs. per baseline per source (normalized by up-time) = 4.3 Min = .0 Max = 23.2 (Baseline Br-Fd on 0402-362) RMS = 3.4 Total time: 1488 minutes ( 24.8 hours). Key: Br=BR-VLBA Fd=FD-VLBA Gc=GILCREEK Hn=HN-VLBA Kk=KOKEE Kp=KP-VLBA La=LA-VLBA Mc=MEDICINA Mk=MK-VLBA Nl=NL-VLBA Gn=NRAO20 Ny=NYALES20 On=ONSALA60 Gg=ORION_5M Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Wf=WESTFORD Br Fd Gc Hn Kk Kp La Mc Mk Nl Gn Ny On Gg Ov Pt Sc Wf Avg % obs. time: 62 60 65 56 63 58 57 37 55 57 57 54 58 62 58 58 51 68 58 % cal. time: 3 3 2 3 2 3 3 2 2 3 3 2 2 2 3 3 2 3 2 % slew time: 24 25 16 23 12 25 25 25 21 26 16 12 16 9 24 25 22 13 20 % idle time: 9 9 14 16 20 12 13 34 20 12 22 30 23 25 13 12 23 15 18 # of tapes : 2.3 2.3 2.3 3.3 2.2 3.3 3.3 3.1 2.2 3.3 2.1 2.1 2.1 2.3 2.3 3.3 2.3 2.3 total # scans: 283 295 252 271 251 291 298 205 254 298 280 221 215 251 276 296 258 276 265 # scans/hour : 11 11 10 10 10 11 12 8 10 12 11 8 8 10 11 11 10 11 11.0 Avg scan (sec): 196 183 233 186 227 179 172 162 193 172 184 221 240 222 190 176 178 221 196 # OF OBSERVATIONS BY BASELINE | Br Fd Gc Hn Kk Kp La Mc Mk Nl Gn Ny On Gg Ov Pt Sc Wf StnTotal -------------------------------------------------------------------------------------- Br|283 271 221 240 207 271 275 135 211 269 242 173 146 209 265 273 220 229 3497 Fd| 295 211 250 208 289 293 132 212 285 258 166 143 218 271 294 239 240 3392 Gc| 252 204 182 212 215 139 182 213 192 191 154 180 204 213 173 194 3632 Hn| 271 167 244 252 144 170 258 248 175 154 224 228 250 239 255 3735 Kk| 251 210 208 83 248 200 182 132 102 153 212 209 155 166 3763 Kp| 291 289 128 214 279 252 164 139 213 272 290 233 234 3568 La| 298 135 212 287 260 170 146 220 271 295 241 242 3440 Mc| 205 81 140 143 166 193 138 119 133 133 150 3309 Mk| 254 203 185 131 100 155 216 213 158 167 3739 Nl| 298 266 174 151 225 262 285 245 251 3246 Gn| 280 170 152 223 235 258 241 248 3443 Ny| 221 182 160 157 168 149 180 3655 On| 215 150 133 144 135 162 3203 Gg| 251 201 218 207 227 3641 Ov| 276 272 215 218 3112 Pt| 296 239 240 2943 Sc| 258 232 3694 Wf| 276 3322 Number of 2-station scans: 48 Number of 3-station scans: 18 Number of 4-station scans: 19 Number of 5-station scans: 13 Number of 6-station scans: 5 Number of 7-station scans: 7 Number of 8-station scans: 8 Number of 9-station scans: 16 Number of 10-station scans: 17 Number of 11-station scans: 19 Number of 12-station scans: 28 Number of 13-station scans: 19 Number of 14-station scans: 26 Number of 15-station scans: 46 Number of 16-station scans: 47 Number of 17-station scans: 33 Number of 18-station scans: 48 Total # of scans, observations: 417 31176 Average baseline components for all observations Average XY = 3732. Average XZ = 3228. Average YZ = 2438. Average length = 4000.