19 September 1999 N. Nitta CHIEF OBSERVER'S REPORT for Week 38 13-Sep-99 to 19-Sep-99 GENERAL Like the previous week, there was only one M-class flare, but the GOES background stayed higher (>B5). Flare mode was triggered by a C2.8 flare, but the flare was so faint that ARS picked up a wrong area. The terminator images in Be filter (used for flare patrol images) show high signals close to the area. SXT TECHNICAL We still have not observed a sufficient number of flares to decide upon the flare threshold. SXT SCIENCE K. Shibata visited from Kyoto, working all night long as usual. For Web material see Current Week: http://isass1.solar.isas.ac.jp/sxt_co/SXTweekly.html Current Week: http://isass1.solar.isas.ac.jp/sxt_co/990917.html Index: http://isass1.solar.isas.ac.jp/sxt_co/index.html This week's science nugget compares SXT and TRACE images to study the relation between hot and cool loops. 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 No change. SEMINARS On 16 September there was a Yohkoh seminar at the D-toh common room. Speaker: Y. Hanaoka, Title: Radio and X-ray Observations of the Flares Caused by Interacting Loops. Nobeyama images at the full 50 ms time resolution were used to locate the acceleration site in flares that appeared to be due to interaction of small and large loops. The Nobeyama data may have not had played such a crucial role before. SXT TABLE PLAN, WEEK 39 (20-Sep-99 to 26-Sep-99) This week, if solar activity continues to be not high, we may continue observing interconnecting loops (IL) as proposed by Joe Khan. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday 19-Sep-99 17:31 1 990919 P1 ARS1 STD Tuesday 20-Sep-99 19:26 3 990920 P3 ARS1 DARK Wednesday 21-Sep-99 16:16 1 990921 P1 ARS0 IL VER1 Wednesday 21-Sep-99 19:40 3 990921 P3 ARS1 STD Thursday 22-Sep-99 16:29 1 990922 P1 ARS0 IL+DIFF Thursday 22-Sep-99 21:36 4 990922 P4 ARS1 STD Friday 23-Sep-99 15:02 1 990923 P1 ARS0 IL VER1 Friday 23-Sep-99 18:25 3 990923 P3 ARS1 STD Saturday 24-Sep-99 15:15 1 990924 P1 ARS0 IL VER1 Saturday 24-Sep-99 18:39 3 990924 P3 ARS1 STD Sunday 25-Sep-99 18:52 3 990925 P3 ARS1 STD This plan is subject to change. 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.