5 September 1998 Nariaki Nitta SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN CHIEF OBSERVER'S REPORT for Week 36 31-Aug-98 to 6-Sep-98 SOLAR ACTIVITY There were more than 10 regions present, and AR 8323 and 8319 were bright. During the first half of the week, the level of solar activity was still quite high, with four M-class flares, but it declined during the second half. This decline seemed to result from AR 8319 disappearing from the west limb and AR 8323 getting stabilized even though ground-based reports said it still had the potential of big flares. We inserted long exposures back in the table. The CME reported on 4-Sep-98 was probably associated with AR 8319 on the basis of its position angle. The French campaign has just started, and the week was peaceful in terms of operations. SXT INSTRUMENT STATUS Compared with the past week, SXT operations were normal, even though there was an SEU, which was cleared at the next pass. The ATT database is not in a good shape with considerable (about 50%) times without HXA data being used. SXT SCIENCE For Web material see Current Week: ftp://isass0.solar.isas.ac.jp/pub/sxt_co/SXTweekly.html Index: ftp://isass0.solar.isas.ac.jp/pub/sxt_co/index.html The science nugget (week 98_36) shows a proton flare in AR 8210. CAMPAIGNS The French group has started a campaign to observe filaments. They are observing at Tenerife. PERSONNEL No Change SEMINARS 3-Sep-98 H. Hara (NAO): "Latitudinal Distribution of XBPs" Impressive result of humps around latitudes=60 deg. TABLE PLAN, WEEK 37 (7-Sep-98 - 13-Sep-98) SXT Chief Observer: Nitta There is a campaign to observe filaments and associated phenomena, in coordination with observations at Tenerife run by Brigitte Schmieder and company. We plan to prepare two tables on Tuesday and Wednesday, one for the campaign at the first pass, and another for normal operations at the second last pass. But later in the week, the Tenerife hours will concide with later passes, so depending on solar conditions we may keep operating in ARS2 during invisible orbits. In other words, the tables with asterisks in the following plan may be changed to ARS2 tables, if the target region is the only region that is likely to flare. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Sunday 6-Sep-98 07:13 2 980906 P2 ARS1 STD DIF Monday 7-Sep-98 10:56 4 980907 P4 ARS1 DARKCAL Tuesday 8-Sep-98 04:24 1 980908 P1 ARS2 MEUDON Tuesday 8-Sep-98 09:30 4 980908 P4 ARS1 STD Wednesday 9-Sep-98 04:40 1 980909 P1 ARS2 MEUDON Wednesday 9-Sep-98 09:48 4 980909 P4 ARS1 STD (*) Thursday 10-Sep-98 06:39 2 980910 P2 ARS1 STD (*) Friday 11-Sep-98 05:14 2 980911 P2 ARS1 STD (*) Saturday 12-Sep-98 07:14 3 980912 P3 ARS1 STD Note that this plan may change during the week. 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, ie 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.