CORE-A054 (Continuous Observations of the Rotation of the Earth-A054) 1999 January 26 Notes prepared by Cynthia Thomas, John Gipson, and Nancy Vandenberg,NVI/GSFC Schedule name: CA054.SKD on CDDISA Nominal Start: 18:00 U.T. on January 26 (day 026) first observation at 18:00 U.T. on 2255-282 for AP-HH-WF first observation at 18:00 U.T. on 4C39.25 for GC-MA-MC Nominal Stop: 18:00 U.T. on January 27 (day 027) last observation at 17:49 U.T. on 0059+581 for GC last observation at 17:55 U.T. on 0048-097 for HH-MA-WF last observation at 17:58 U.T. on 0003-066 for AP-MC 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) 280 72828201 Fairbanks A GC 1 (TT) 223 40476601 HartRAO J HH 1 (TT) 143 72326201 Matera I MA 3 (HDT) 313 72435701 Medicina B MC 2 (HDT) 319 72308801 Westford E WF 1 (TT) 305 72097301 Purpose ======= The purpose of CORE-A is to validate the CORE concept of measuring EOP continuously using different networks. Comparisons of the EOP results from simultaneous sessions in 1997 and 1998 have shown fairly good agreement, but there are some puzzling systematic differences. It is hoped that additional data to be obtained during 1999 will contribute to understanding this data set. The network for CORE-A includes Fairbanks, HartRAO, Algonquin, Westford, Matera, Medicina, Tsukuba, and Hobart. Tsukuba will begin to participate in CORE-A after April 1. This set of 8 stations includes two geographically paired stations: Algonquin/Westford and Matera/Medicina. For purposes of comparison with NEOS, we want to keep this network as constant as possible but we need to limit the network size to 6 stations. Whenever Tsukuba is available during non-network periods, we will drop Matera. Whenever Hobart is available we will drop Westford. Schedule ======== This is a new schedule generated by C. Thomas with the automatic mode of sked. The characteristics of the CORE-A schedules have changed slightly because HartRAO is the only station in the southern hemisphere. Changes were made in order to increase the number of observations at HartRAO and to smooth out the distribution of observations over the sky. Following are the characteristics of the CORE-A schedule file: 1) This schedule was optimized for sky coverage. 2) Only the observations in the previous 3 hours of the schedule were considered for the minor options. The best 50% 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 thirty minutes. 5) The minimum SNR limits for the baselines were set to 20 for X-band and 15 for S-band, with the exception of the HartRAO baselines. The minimum SNR limits for the HartRAO baselines were set to 15 for X-bannd and 12 for S-band. 6) This schedule was made using 63 sources which helped improve the sky coverage. Simulation Results ================== Simulated data from this schedule was used in a global solution to estimate the formal errors. The table below lists the formal errors for Earth orientation parameters. These results meet the simulation goals for the CORE-A network. Also shown in the table are the maximum correlations between the Earth orientation parameters and other parameters. The results from the 1998 CORE-A network showed very high (~70%) correlations between certain parameters and this was one of the motivations for re-design of the network. ____________________________________________ | | | | | | EOP |Formal| Other | | |Parameters |Errors|Parameters|Correlation| |____________|______|_________ |___________| | | | | | |X-Wobble | 68.00| UT1-TAI | 43% | | | | | | |Y-Wobble | 48.81| UT1-TAI | 50% | | | | | | |UT1-TAI | 2.26| Y-Wobble | 50% | | | | | | |UT1-TAI Rate| 5.35| ------- | under 40% | | | | | | ____________________________________________ 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 following databases: Date Experiment ==== ========== 98SEP22 CORE-A045 98SEP29 NEOS-A283 98OCT06 NEOS-A284 98OCT06 CORE-A046 98OCT20 NEOS-A286 98OCT20 CORE-A047 98NOV03 NEOS-A288 Procedures ========== Please generate the procedures for this session using drudg. Correlation ========== This experiment will be correlated at the Washington Correlator with all baselines being correlated. SKED Summary from file ./ca054.skd for experiment CA054 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066Ixx x x x x xx x xI 10 27 4.5 0048-097I x x x x x x x x x I 9 49 7.7 0059+581I x x x x x x x x x x x x x xx x x x I 18 168 14.0 0106+013I x I 1 1 .1 0119+115I x x x x x xx I 7 30 3.8 0119+041I x xx xx I 5 15 2.1 0229+131I xx x x x I 5 15 2.0 0235+164I xx x xx x x x x I 9 46 6.2 3C84 I x x x x x x x x xx x x x x x x x x xI 19 19 1.8 CTA26 I x x x x x x x x x I 9 25 3.8 0402-362I x x x I 3 5 2.1 0454-234Ix x x xx x x xxx x I 11 42 10.4 0458-020Ix x I 2 9 1.4 0528+134Ix x x xx x x x xx x I 11 72 9.5 0552+398I x x x x x x x x x x x x x x x x xI 17 133 13.9 0556+238I x x I 2 2 .2 0718+793I x x I 2 12 1.0 0727-115Ix x x xx x x x x x xx I 12 48 7.6 0749+540I x x x x x xx x x x x x xI 13 122 10.3 0804+499I x x x x x x x I 7 63 5.9 0805+410I x I 1 3 .2 0823+033I x xx x x x x x xx I 10 23 3.3 OJ287 I x x x x x xx x x x I 10 40 4.8 0919-260Ix x x x x xx I 7 7 2.2 0920-397Ix I 1 1 1.0 4C39.25 I xx x x x x x x x xx x x x x x xx x x x x xI 23 172 17.5 OK290 I x x I 2 4 .4 0955+476I x x x I 3 26 2.5 1034-293I x x x x xI 5 11 2.7 1044+719I x x x x x x x x x x xI 11 106 8.8 1053+815I x I 1 10 .8 1124-186I x x xx x x x xx x x I 11 42 10.1 1128+385I I 0 0 .0 1144-379Ixx x x x I 5 5 1.7 1219+044I x x x x x xx x xx I 10 37 5.3 3C273B I xx x x x xI 6 6 .8 1255-316I x x I 2 2 1.3 1300+580I I 0 0 .0 1313-333I I 0 0 .0 1334-127I x x x x x x x I 7 14 2.5 1351-018I x I 1 3 .5 1357+769I x x x x x I 5 46 3.8 1424-418I x x I 2 2 .8 1451-375I x x x I 3 3 2.5 1606+106I x x x x xx I 6 21 2.8 1622-253I x xx x x x x x I 8 21 5.0 NRAO512 Ix x xx x xx x x xx x xx x x x x x x I 20 152 15.3 3C345 I x x I 2 2 .2 1726+455I x I 1 3 .3 1739+522I x x x x xx x x xx x x x x x x x x xx x xI 22 190 16.7 1741-038I x x x x x x x xxxx xxx x I 15 74 11.5 1749+096I xx x x x x xx x xx x x x I 14 87 12.1 1908-201I x x xx x x x I 7 13 3.0 1921-293I x x x x x x x x I 8 18 4.6 1954-388I x x x x I 4 8 3.9 1958-179I I 0 0 .0 2121+053I xx x x x x x x I 8 41 5.8 2128-123I x x I 2 2 .4 2134+00 I x x x x x xx x x x I 10 10 1.5 2145+067I x x x x x x x x x xI 10 39 5.5 2234+282Ix x x x x x x x x x x I 11 75 8.5 3C454.3 I x x x xx x x x x x x x I 12 12 1.5 2255-282I x x x x x I 5 11 3.7 Total scans, obs: 463 2245 Average number of obs. per baseline per source (normalized by up-time) = 4.7 Min = .0 Max = 26.2 (Baseline Ma-Mc on 4C39.25 ) RMS = 6.2 Total time: 1440 minutes ( 24.0 hours). Key: Ap=ALGOPARK Gc=GILCREEK Hh=HARTRAO Ma=MATERA Mc=MEDICINA Wf=WESTFORD Ap Gc Hh Ma Mc Wf Avg % obs. time: 23 29 20 40 29 43 31 % cal. time: 3 2 1 3 3 3 3 % slew time: 55 14 27 17 36 12 27 % idle time: 17 54 50 37 30 40 38 # of tapes : 1.5 .5 .4 2.4 1.8 .8 total # scans: 280 223 143 313 319 305 263 # scans/hour : 11 9 5 13 13 12 11.0 Avg scan (sec): 71 112 124 113 79 123 103 # OF OBSERVATIONS BY BASELINE | Ap Gc Hh Ma Mc Wf StnTotal -------------------------------------- Ap|280 186 41 136 155 277 638 Gc| 223 19 133 151 199 805 Hh| 143 136 123 55 693 Ma| 313 298 159 746 Mc| 319 177 796 Wf| 305 812 Number of 2-station scans: 124 Number of 3-station scans: 160 Number of 4-station scans: 51 Number of 5-station scans: 117 Number of 6-station scans: 11 Total # of scans, observations: 463 2245 Average baseline components for all observations Average XY = 4256. Average XZ = 3840. Average YZ = 3937. Average length = 5125.