CORE-B108 (Continuous Observations of the Rotation of the Earth-B108) 1998 April 08 Notes prepared by Cynthia Thomas, NVI/GSFC Schedule name: CB108.SKD on CDDIS Nominal Start: 18:30 U.T. on April 08 (day 098) first observation at 18:30 U.T. on 0059+581 for AP-FT-GC-KA- ON-WZ first observation at 19:50 U.T. on 1357+769 for 15 Duration: 24 hours Nominal Stop: 18:30 U.T. on April 09 (day 099) last observation at 17:12 U.T. on 0718+793 for 15 last observation at 18:26 U.T. on 1741-038 for GC-KA last observation at 18:26 U.T. on 0458-020 for ON-WZ last observation at 18:30 U.T. on 0454-234 for AP-FT Correlator: Haystack **Frequency Sequence**: CDPSX - Standard CDP SX sequence. (360 MHz wide at X, 85 MHz wide at S) 1 letter 2 letter Station Code Code # of tapes # of obs Occupation Code Algonquin G AP 2 (HDT) 253 72828201 DSS15 D 15 1 (TT) 257 72318701 Fortaleza F FT 2 (HDT) 124 72974801 Fairbanks A GC 1 (TT) 283 40476601 Kashima-26 Q KA 3 (HDT) 200 18567601 Onsala T ON 3 (HDT) 212 72137701 Wettzell V WZ 3 (HDT) 261 72247801 Purpose ======= The purpose of the CORE-B sessions is to provide additional data for comparison of EOP measurements and to obtain long 48-hour data sets for geophysical studies. The analysis of CORE-A and CORE-B has concentrated on comparing the EOP results from these sessions with the NEOS sessions. Preliminary results of the comparisons show that, while the EOP results generally agree between different networks, there are systematic differences that are not fully understood. Because of these discrepancies, it was decided that an improved comparison could be made if the CORE-A, NEOS, and CORE-B could all be compared for the same day, making possible a 3-way comparison. Therefore we will run the CORE-B sessions on days adjacent to the CORE-A/NEOS days instead of on the alternate week. This plan will concentrate the observing days but it will provide more a robust data set for understanding the differences. 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 two hours of the schedule were considered for the minor options. The best 60% 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 50 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. Station Information =================== Yellowknife will not be able to participate in the experiment because their maser is not operational and they do not have any tape heads. Ny Alesund was asked to participate in place of Yellowknife but the Ny Alesund personnel will be on Easter holiday. Procedures ========== There are no special procedures for this experiment. Please use your standard SGP procedures. Correlation ========== This experiment will be correlated at the Haystack Correlator with all baselines being correlated. SKED Summary from file ./cb108.skd for experiment CB108 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x x xx xx x x I 9 26 3.1 0048-097I x x x I 3 7 .9 0059+581Ix x x x x x x x xx x xx x x x x x I 18 272 15.6 0106+013I I 0 0 .0 0119+115I I 0 0 .0 0119+041I I 0 0 .0 0229+131I x x x x I 4 6 .5 0235+164I xx x x x x x x I 8 17 1.5 CTA26 I x x xx xx x x x x xI 11 19 2.1 0454-234I x x x x x xx xI 8 16 3.0 0458-020I x x x x x x x I 7 13 1.4 0528+134Ix x x x x x xxx xxx xx x x I 16 65 5.9 0552+398Ixx xx x xx x xx x x x x xx x x xx x x x x I 24 241 16.3 0556+238I x x x x I 4 18 1.4 0718+793I x x x x x x x x x x xI 11 27 1.3 0727-115Ix x x xxx xx xxx x x x x x x I 17 48 6.8 0749+540Ix x x x x xx x x x x x x x x x x x x x x I 21 264 14.5 0804+499I x I 1 15 1.0 0805+410I x x x x x x I 6 33 2.1 0823+033I x x x x x x x I 7 18 1.8 OJ287 I x x xx xxx xx x x I 11 19 1.6 0919-260Ix x x x x I 5 5 1.2 4C39.25 I x x x xx xx xx xx xx x x x x x x x x x x I 23 247 17.2 OK290 I x x x x x x x x I 8 20 1.7 0955+476I x x I 2 30 1.8 1044+719I x x x x x x x x x I 9 131 6.6 1053+815I x x I 2 6 .4 1124-186I x x xxx x I 6 10 1.6 1128+385I xI 1 6 .4 1219+044I x x xx x x x x I 8 21 2.1 1300+580I x x x x x I 5 27 1.4 1308+326I x x x x x x x x xx x x I 12 39 2.9 1334-127Ixx x x x x x xx x x x xI 13 34 4.6 1351-018I x x x x x I 5 9 1.0 1357+769I x x x x x x x xI 8 86 4.1 1606+106I x x xx xx xx x x x x xI 13 70 6.6 1622-253I xx x x x x I 6 6 .9 NRAO512 Ixx x x x x x x x x x x x I 13 130 8.8 1726+455I x I 1 10 .6 1739+522I x x x x x x x x x x x x x x xx x xI 18 240 14.5 1741-038I xxx xxx x x x xx xx xx xx xxxI 20 65 7.3 1749+096I x x x xx xx x xx xI 11 46 4.4 1908-201I x x x x I 4 12 2.1 1958-179I x x x x I 4 8 1.3 2121+053I x xx x x x x I 7 15 1.5 2128-123I x xx x xx xx x x x x x I 13 25 4.3 2134+00 I x xx xx x xx xx xxx xx I 15 15 1.6 2145+067Ix x x x x x x x x x x x x I 13 59 5.8 2234+282I x x x x x x I 6 21 1.6 2255-282I xx x x x I 5 13 3.3 Total scans, obs: 442 2530 Average number of obs. per baseline per source (normalized by up-time) = 3.9 Min = .0 Max = 33.1 (Baseline On-Wz on 2134+00 ) RMS = 5.9 Total time: 1441 minutes ( 24.0 hours). Key: Ap=ALGOPARK 15=DSS15 Ft=FORTLEZA Gc=GILCREEK Ka=KASHIMA On=ONSALA60 Wz=WETTZELL Ap 15 Ft Gc Ka On Wz Avg % obs. time: 22 28 28 35 36 37 36 32 % cal. time: 2 2 1 3 2 2 3 2 % slew time: 56 31 20 19 19 17 11 25 % idle time: 17 37 49 42 41 42 48 39 # of tapes : 1.4 .5 1.8 .6 2.2 2.3 2.2 total # scans: 253 257 124 283 200 212 261 227 # scans/hour : 10 10 5 11 8 8 10 9.5 Avg scan (sec): 76 95 199 108 157 153 121 129 # OF OBSERVATIONS BY BASELINE | Ap 15 Ft Gc Ka On Wz StnTotal ------------------------------------------ Ap|253 197 88 187 92 113 139 722 15| 257 74 205 117 97 103 894 Ft| 124 53 15 69 84 697 Gc| 283 168 139 151 632 Ka| 200 122 119 696 On| 212 198 522 Wz| 261 897 Number of 2-station scans: 124 Number of 3-station scans: 132 Number of 4-station scans: 63 Number of 5-station scans: 51 Number of 6-station scans: 65 Number of 7-station scans: 7 Total # of scans, observations: 442 2530 Average baseline components for all observations Average XY = 5561. Average XZ = 4483. Average YZ = 4079. Average length = 6013.