5 October 1998 Hugh Hudson David McKenzie SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN CHIEF OBSERVER'S REPORT for Week 40 29-Sep-98 to 4-Oct-98 GENERAL Yohkoh SXT has performed with no difficulty this week, aside from one mis-communication between the CO and the KSC tohbans. The highlight of the solar activity was the M flare over the NW limb on 30-Sep. This was observed by SXT PFIs and TRACE in the late phase, and probably in Yohkoh flare mode during the event itself. J.-P. Wuelser has finished his improvements of the ATT database and made a bit of a breakthrough in his initial analysis of the HXA scan data, to see if they might replace the limb addresses. A full report will be provided for discussion on Oct. 12. SXT TECHNICAL Acton completed a study of the SXT gain with intereting and/or disturbing news. Details follow. A new Normal Point was requested, to be scheduled October 5 JST we hope. We have not yet automated this process (scheduling pointing revisions) and somebody needs to re-visit the "commanded pointing" algorithm. SXT SCIENCE For Web material see Current Week: http://www.solar.isas.ac.jp/sxt_co/SXTweekly.html Index: http://www.solar.isas.ac.jp/sxt_co/index.html The science nugget (week 98_40) shows a _cool_ looptop source in an M flare simultaneously observed by EIT and by SXT. How can this be? Is there a filament (hearken back to the "chewy nougat") caught in the act of rising and heating? Is a lump of transition-region material being ejected, as perhaps suggested by numerical simulations of spicules? This flare shows strong ejection, but in an almost horizontal direction, quite different from what filaments normally display - we think. CAMPAIGNS Louise Harra-Murnion (TRACE/Norikura) continued, with solid rain at Norikura but clear skies at TRACE. Finally, on the last day of the run at Norikura, Jagdev Singh achieved clear skies. Both TRACE and Yohkoh data are available, and there were phenomena in the region being observed. PERSONNEL J.-P. Wuelser returned to Palo Alto; D. McKenzie arrived from Bozeman. SEMINARS None (Astronomical Society meeting) TABLE PLAN, WEEK 41 (03-Oct-98 - 10-Oct-98) We look forward to synchronizing again with SOHO. There seem to be no coordinated observations planned for this week. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Sunday 3-Oct-98 18:45 2 981003 P2 ARS1 STD Tuesday 5-Oct-98 21:01 4 981005 P4 ARS1 DARKCAL Wednesday 6-Oct-98 17:52 2 981006 P2 ARS1 DIF Thursday 7-Oct-98 18:09 3 981007 P3 ARS1 STD Friday 8-Oct-98 20:10 4 981008 P4 ARS1 STD Saturday 9-Oct-98 18:44 4 981009 P4 ARS1 STD Sunday 10-Oct-98 19:01 4 981010 P4 ARS1 STD NOTE THAT THIS PLAN IS DIFFERENT THAN THE ONE MAILED TO YOU EARLIER. Note that the naming convention uses the UT day number of the first pass of the day. 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.