CORE-A039 (Continuous Observations of the Rotation of the Earth-A039) 1998 June 30 Notes prepared by Cynthia Thomas, NVI/GSFC Schedule name: CA039.SKD on CDDIS Nominal Start: 18:00 U.T. on June 30 (day 181) first observation at 18:00 U.T. on 4C39.25 for AP-GC-MA-WF first observation at 18:00 U.T. on 1451-375 for HH-HO Duration: 24 hours Nominal Stop: 18:00 U.T. on July 01 (day 182) last observation at 17:57 U.T. on 1958-179 for HH-HO last observation at 18:02 U.T. on 4C39.25 for AP-GC-MA-WF Correlator: Washington **Frequency Sequence**: CDP-WBCA - Modified CDP wide-band SX sequence. (720 MHz wide at X, 125 MHz wide at S), Shifted to avoid RFI at Matera 1 letter 2 letter Station Code Code # of tapes # of obs Occupation Code Algonquin G AP 2 (HDT) 328 72828201 Fairbanks A GC 1 (TT) 321 40476601 HartRAO J HH 3 (HDT) 226 72326201 Hobart H HO 2 (HDT) 171 72425901 Matera I MA 3 (HDT) 305 72435701 Westford E WF 1 (TT) 350 72097301 Purpose ======= The CORE-A sessions measure EOP simultaneously with NEOS, using an independent network of comparable or better precision. The purpose of the parallel sessions is to assess the true accuracy of VLBI results for EOP by comparing the measurements from the two networks. Note on Core-A 1998 results to date: As of early January 1998, 18 CORE-A sessions from 1997 have been completed and analyzed. The comparisons of the EOP results from these sessions with NEOS are quite encouraging. The levels of agreement for daily measurements are 125 micro-arcsec for X-pole, 105 micro-arcsec for Y-pole, and 7.4 microsec for UT1 and 20 microsec for LOD. The corresponding Chi-squares per degree of freedom are 1.2, 1.3, 2.2, and 2.4, respectively. The goals for EOP in the Mark IV era are 25 micro-arcsec for the pole components and 1 microsec for UT1. (No goal for LOD has been set.) We have a lot of work remaining, but these goals are not out of reach. Schedule ======== This is a new schedule generated by C. Thomas with the automatic mode of sked. The following are the characteristics of the schedule: 1) This schedule was optimized for sky coverage. 2) Only the observations in the previous hour of the schedule were considered for the minor options. The best 70% of the configurations were considered for minor options. 3) The "minor options" were set to select observations to maximize the total number of observations, to minimize the idle time between scans, and to minimize time between scans on the same source by twenty minutes. 5) The minimum SNR limits for most baselines were set to 20 for X-band and 15 for S-band. 6) This schedule was made using 59 sources which helped improve the sky coverage. Flux Information ================ Several years ago John Gipson wrote a program called snranal which compares the measured performance of an experiment with respect to the predicted. One of the things this program calculates is an empirical flux density for each source. Recently J. Gipson compared the fluxes generated by this program with those from more careful modeling. The agreement is generally good (~15%) for those sources which have been observed more than 20 times. In order to account for changes in the flux catalog since the last update, J. Gipson adjusted the fluxes in the flux catalog for the sources in the current source catalog using the 98Mar03 NEOS-A253 and the 98JAN27XA CORE-A028 experiments. Procedures ========== Please use the modified CDP Wide-band SX sequence, CDP-WBCA, for this experiment. Correlation ========== This experiment will be correlated at the Washington Correlator with all baselines being correlated. SKED Summary from file ./ca039.skd for experiment CA039 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x xx xx I 5 7 1.2 0048-097Ix xx xx x x xx x x x x x x I 15 36 5.9 0059+581I x x x x x x x x x x x x x x x x xI 17 99 9.9 0104-408Ix x xx xx x x x xI 10 14 4.4 0106+013I xx x xx I 5 5 .8 0119+115Ix x x x x x x x x x I 10 23 3.0 0119+041I x I 1 3 .4 0208-512I x x x xx I 5 5 2.0 0229+131I x x x x x x x x xI 9 18 2.3 0235+164I x x I 2 2 .3 CTA26 I x x x x x xx I 7 15 2.4 0402-362I xx xx xx x x x x x I 11 15 4.9 0454-234I x xxxx x xxx x x x x I 13 17 3.4 0458-020I x x x x xx x xx I 9 13 2.1 0530-727I I 0 0 .0 0528+134I xx x x xx x x x xx xx xx I 15 43 5.7 0537-441I I 0 0 .0 0552+398Ix x x xx xx xx xx x x x xx xx xx x x x x I 24 111 12.8 0556+238I I 0 0 .0 0637-752I x x x x x x x x x I 9 9 3.7 0718+793I x x x x I 4 12 1.2 0727-115I x x x x xx xx xx xxx xx x xx x xI 20 36 7.0 0749+540I xx x x x x x x x x x x x x x x xxI 18 99 10.0 0804+499I x x x x I 4 24 2.7 0805+410Ixx x x x x x x x x x x x x x x x x I 18 57 5.5 0823+033Ix x x x x x x x x I 9 23 3.3 OJ287 I x x xx I 4 4 .5 0919-260I x x I 2 2 .8 0920-397I x I 1 1 .3 4C39.25 Ix x x x xx x x xx x x x xxx xx x xx x xx x I 26 125 12.9 OK290 I x x x x x x x I 7 17 1.8 0955+476Ix x xx x xx x x xx xx x xx x x x x I 20 82 9.5 1034-293I x x x x I 4 4 1.4 1044+719Ix x x x x x x x x x x x x x x x x I 17 99 9.9 1053+815I I 0 0 .0 1057-797I x x x x x x x I 7 7 2.9 1104-445I I 0 0 .0 1124-186I x x x x x xI 6 6 1.3 1128+385Ix x x x x x I 6 12 1.0 1144-379I xx x x x x x I 7 7 2.4 1219+044I xxx x x x I 6 14 2.0 1255-316I I 0 0 .0 1300+580I x I 1 3 .3 1308+326I x xx xx xx x x x x I 11 19 1.9 1313-333I x x x x x x I 6 6 1.8 1334-127I x x x x xx xx xx x x x x I 14 20 3.3 1351-018I xx x I 3 9 1.5 1357+769Ix x x x x x x x x x x x x x x x I 16 96 9.6 1424-418I x xx xx x x x I 8 8 2.7 1451-375I x I 1 1 .3 1606+106I x x x x x x xxx xxx x x x x xx x x I 20 42 5.5 1610-771I x x x x x x x x I 8 8 3.3 1622-253I x xx x xI 5 5 1.6 NRAO512 I x xx x x x x x x xx x x x x x xI 17 82 9.5 1726+455I x x xx x x x xI 8 32 3.8 1739+522I x x x x x x x xx x x xx xx x xI 17 96 10.2 1741-038I x x xx x xxxx xx x xx x xxx xxx xxx I 24 52 8.3 1749+096I xx x xx x x x x x x x x x xx I 16 45 6.3 1815-553I x x I 2 2 .8 1908-201Ixx x xx x x x x x I 10 10 2.4 1921-293Ixxx x x x x x xxxxx x xxxx I 18 20 4.9 1954-388I x x x x x x xx xxI 10 10 3.3 1958-179I x x x x x x I 6 8 1.7 2005-489I I 0 0 .0 2052-474I I 0 0 .0 2121+053I x x xx I 4 4 .6 2128-123I x x x x xx x x x xx I 11 15 2.6 2134+00 I x x x x I 4 4 .6 2145+067I xx x x x x xx x x xx xx x xxI 17 31 4.3 2234+282I x x I 2 6 .6 2255-282I x x x x x x xx x I 9 15 4.1 Total scans, obs: 621 1715 Average number of obs. per baseline per source (normalized by up-time) = 3.5 Min = .0 Max = 29.3 (Baseline Hh-Ma on 4C39.25 ) RMS = 5.8 Total time: 1443 minutes ( 24.1 hours). Key: Ap=ALGOPARK Gc=GILCREEK Hh=HARTRAO Ho=HOBART26 Ma=MATERA Wf=WESTFORD Ap Gc Hh Ho Ma Wf Avg % obs. time: 26 41 38 32 40 45 37 % cal. time: 3 3 2 1 3 4 3 % slew time: 54 18 43 23 17 12 28 % idle time: 14 36 14 41 38 37 30 # of tapes : 1.8 .7 2.4 2.0 2.4 .8 total # scans: 328 321 226 171 305 350 283 # scans/hour : 13 13 9 7 12 14 11.8 Avg scan (sec): 71 112 148 164 114 113 120 # OF OBSERVATIONS BY BASELINE | Ap Gc Hh Ho Ma Wf StnTotal -------------------------------------- Ap|328 237 26 5 161 319 592 Gc| 321 19 46 176 238 771 Hh| 226 119 122 34 306 Ho| 171 18 7 625 Ma| 305 188 767 Wf| 350 369 Number of 2-station scans: 325 Number of 3-station scans: 146 Number of 4-station scans: 137 Number of 5-station scans: 13 Number of 6-station scans: 0 Total # of scans, observations: 621 1715 Average baseline components for all observations Average XY = 4879. Average XZ = 4588. Average YZ = 3990. Average length = 5750.