30 October 1999 L. Fletcher D. McKenzie CHIEF OBSERVER'S REPORT for Week 44 25-Oct-99 to 30-Oct-99 GENERAL Solar activity started and finished low, but was somewhat elevated in the middle of the week. The GOES X-ray baseline was at high B and low C level. Active regions 8737, 8739, 8741 and 8742 produced several good M flares and C flares, including one M3.7 event on the west limb. SXT TECHNICAL The instrument continued to perform well all week. The CCD blooming in NaBan straylight monitor images, reported last week, did not recur; increased flushing of the CCD before these images seems to have removed the problem. On 25-October-99 the flare-patrol images were changed from Be/Op, DPE=13 (which they had been since 1-Sept-99) back to A2/Op, DPE 11, which they had been previous to that. This was in response to a number of instances in which a flare-trigger had occurred but SXT had pointed to the lower-left location of the patrol frame. We think that with the thicker Be/Op combination, the flare location could not be identified, and the instrument had pointed at some default position. Since changing the flare patrol filter, this bad pointing has not recurred. However, we will keep the situation under review as solar activity climbs. For Web material see Current Week: http://isass1.solar.isas.ac.jp/sxt_co/991029.html Index: http://isass1.solar.isas.ac.jp/sxt_co/index.html This week's science nugget describes a limb flare successfully observed by SXT, in which an above-the-looptop HXR source was also seen. CAMPAIGNS For SXT plans, see: http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html For SXT completed campaigns, see: http://isass1.solar.isas.ac.jp/sxt_co/sxt_catalog.html PERSONNEL Hugh Hudson returned from GSFC on Thursday. SEMINARS There was a seminar on Thursday "Stochastic Simulations of (flare) Particle Acceleration and Transport" by Lyndsay Fletcher, LMSAL. SXT TABLE PLAN, WEEK 45 (01-Nov-99 to 06-Nov-99) This week SXT will devote Monday to SUMER/TRACE/et al JOP104. See http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html for details. Expect to use ARS2 Monday, and PFI-dominant (ARS0) for a few orbits on Wednesday and Thursday, possibly to study interconnecting loops. Note that this is a change from the draft plan sent out earlier. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday 31-OCT-99 22:05 1 991031 P1 ARS2 DIFF+J104 Tuesday 01-NOV-99 20:37 1 991101 P1 ARS1 DARKCAL Wednesday 02-NOV-99 22:32 2 991102 P2 ARS0 STD+IL Wednesday 03-NOV-99 01:57 4 991102 P4 ARS1 STD Thursday 03-NOV-99 21:03 1 991103 P1 ARS0 STD+IL Thursday 04-NOV-99 00:27 3 991103 P3 ARS1 STD Friday 04-NOV-99 21:16 2 991104 P2 ARS1 STD Saturday 05-NOV-99 19:47 1 991105 P1 ARS1 STD NOTE THAT SOME OF THE TABLE ID NAMES LOOK STRANGE. This is because of the convention of naming each table according to the UT date of the FIRST PASS OF THE KSC DAY. This plan is subject to change all over again. Continuing requests: KSC & SSOC Tohbans: If any KSC passes are likely to be cancelled (for example due to a typhoon) or an SXT table cannot be uploaded for some reason, please telephone and e-mail the Chief Observer immediately. (sxt_co@isass0.solar.isas.ac.jp, copy to sxt_st@flare2.solar.isas.ac.jp). SSOC Tohban: On the weekly visible diagram, please mark the official five passes first and then cross out those passes that will be given to other satellites. That way we can keep the numbering straight in the Yohkoh software system. SSOC Tohban: SXT operations do not currently include terminator off- pointing. It is unnecessary this week to ask the SXT Chief Observer for terminator off-pointing information. KSC Tohbans: In general flare mode supersedes table upload, i.e. if a flare is in progress please do not upload a new table, and contact the chief observer. Normally it is OK to go ahead with the planned table without change on the next pass, if it is available. Chief observers should keep an eye on this.