SSOC TOHBAN REPORT FOR WEEK 16 (18 - 24 April 1994) Prepared on 23 April 1994 D. Alexander and S. Watari 1 SOLAR ACTIVITY 1.1 The Sun was relatively active last week with 5 2 events exceeding the GOES C1 level. The largest being a C5 event. 2 STANDARD OPERATIONS 2.1 SXT table uploads Date(UT) Pass ID -------- ---- -- Apr.19 940419-0103 940419 P2 ARS1 STH OFFPNT1 Apr.20 940420-0207 940420 P4 ARS1 DKCAL Apr.21 940421-0001 940421 P2 ARS1 STH OFF T Apr.22 940412-0205 940412 P4 ARS1 STD 2.2 STT Timer Set - Executed on 19 April. Next STT Timer Set should be executed on 26 April. 2.3 QUIET RATE MEDIUM was inserted in SAA's wherever possible. 2.4 Offset pointing South offpoints were performed to obtain terminator images to support the observations of the south coronal hole made in the previous week. These offpoints were carried out by OP and so the OP number is given. offpoint 8' south (Apr.19 03:30 UT; 940418-1547 OP) normal point (Apr.19 03:34 UT; 940418-1547 OP) offpoint 8' south (Apr.19 05:07 UT; 940418-1547 OP) normal point (Apr.19 05:17 UT; 940418-1547 OP) offpoint 8' south (Apr.21 04:09 UT; 940421-0208 OP) normal point (Apr.21 04:44 UT; 940421-0208 OP) offpoint 8' south (Apr.25 03:48 UT; 940424-1341 OP) normal point (Apr.25 04:18 UT; 940424-1341 OP) offpoint 8' south (Apr.25 07:03 UT; 940424-1341 OP) normal point (Apr.25 07:40 UT; 940424-1341 OP) 3 SPECIAL OPERATIONS 3.1 Eclipse Rehearsal Rehearsal of planned eclipse observations was carried out on 22-Apr-94 Pass 3 (940422-0101) 3.2 KSC 20m antenna repair Due to the antenna repair, the operation on Apr. 23 (Sat) was cancelled. 4 ERRORS AND PROBLEMS 4.1 Instrument Errors BCS error occurred on 18-Apr-94 at Pass 1 (940417-1547) A successful BCS recovery was carried out on 18-Apr-94 at Pass 2 (940418-0102) 4.2 On Tuesday (Apr.19) we could not send the OP table to the mainframe SSOC#01. This was a recurrence of the problem mentioned by the previous week's tohbans. The problem was solved by first attempting to condense the file but there was not enough space on the disk. We therefore deleted the old OP files in 'SR0001.OPSEQ.INFILE' and the OP table could be then be transferred successfully. We recommend that future tohbans delete these files regularly. 4.3 False flares - There were a total of 5 flase flare flags this last week; 2 on Apr. 17, 1 on Apr. 18 and 2 on Apr. 19. All of these were associated with exits from SAA. In particular, the false events which occurred on 17-Apr-94 at 05:11 and 06:58 UT could be related to the large increase in geomagnetic activity at these times; a geomagnetic index of 69 was recorded for this day. The disturbance of the radiation belt due to this large geomagnetic effect may have lasted several days and this may have been responsible for the false flares recorded later in the week. The effect of such false flare flags on campaign observations may be severe and it is therefore necessary to devise optimal operational conditions during campaigns. 4.4 Software problems - There is a bug in the op_first_guess software when preparing weekend schedule. In order to obtain correct number of pass sheets for weekend operations, op_first_guess must be run twice. This should be reported to Lemen-san and hopefully corrected. 4.5 Check List - There are several mistakes in the current version of the tohban check list. We have corrected these manually for the available sheets but a new check list should be prepared with the correct information. 4.6 E-mail - There were some minor problems with e-mail. The addresses for Imasaki-san (?) and Ken Phillips at RAL do not work and these people failed to receive last week's tohban report. 4.7 Other points for discussion 2nd KDD called and offerred us a cheaper line for our long distance calls. Should perhaps be considered. 5 DSN COMMUNICATIONS There were many problems with DSN communications this week, partly due to the extended holiday and partly due to the sudden cancellation of five DSN passes for the supposrt of a rocket launch. In addition, DSN managed to get some of the pass times wrong. This applied once this week but we noticed errors in future weeks schedules. Wrong pass times cause problems in OP first guess. Tohbans should be vigilant and alert to these problems. 5 DSN passes at Canberra (DSS-46) were cancelled at short notice on 21 and 22 April. This sudden cancellation forced us to upload a new OP table at Pass 4 on April 21 to avoid porblems. SSOC tohbans further deleted 2 DSN passes, one for April 23 and one for April 24, to enable weekend operations. Requested re-transmission of complete data from 20:46 05-April-94. 6 HIKITSUGI 6.1 Yohkoh/Asca Pass Conflicts In the week 16, there was no conflict between Yohkoh passes and Asca ones. Preparing the schedule for week 17 we found no conflicts between the Yohkoh and Asca operations. However, the passes are getting closer and tohbans should again be careful when preparing the schedule for week 18. 6.2 The fax machine in the Asca operation room has frequently troubled. Most of the troubles were due to paper jam. This was reported by the last tohbans and has still not been fixed. 6.3 Two offpoints are planned for Monday 25 April. Tohbans should carry out check list instructions for offpoints on Tuesday. SXT Chief Observer is expected to require further offpoints during the week 17. Alexander will be available to help in changing OP Table for these observations. 6.4 Two campaigns are planned for week 17; a rocket flight campaign on 25-April and an XBP campaign from 27-April to 1 May. 6.5 Tohbans for W17 (Apr 25-May 1): SSOC: Tsuneta and Jiao KSC: Hara and Shoji