24 August 1998 David Alexander SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN CHIEF OBSERVER'S REPORT for Week 34 17-Aug-98 to 23-Aug-98 SOLAR ACTIVITY The level of solar activity picked up considerably with the appearance of AR8307 which produced several M- and X-class flares. Many of these occurred during Yohkoh day and one, in particular, was detected during a real-time contact. The Whole Sun Fortnight (WSF) campaign continued with various targets including: AR8303 + southern extension of north polar coronal hole; AR8304 in the south with some interesting sigmoid shaped loops; AR8307 with many flares. There was an solar eclipse on 21/22-Aug-98 and a special table was prepared. Yohkoh saw 4 episodes of this eclipses and we should have good coverage of, at least, 3 of these. SXT INSTRUMENT STATUS SXT has been working fine, no new problems to report. 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 of week 98_34 shows the X4 eruptive flare of 16-Aug-98 22:20 UT detected in Yohkoh real-time data.. CAMPAIGNS Whole Sun Fortnight continues. This coordination continues through 25-Aug-98. PERSONNEL Hugh Hudson return from the US. SXT TABLE PLAN FOR WEEK 98_35 (24-Aug-98 - 30-Aug-98) SXT Chief Observer: Alexander The Whole Sun Fortnight campaign continues this week until Thursday. This campaign is a curtailed version of the Second Whole Sun Month campaign because of the problems with SoHO. Specific targets will be selected to carry out a number of objectives. THIS IS A MODIFIED TABLE PLAN WHICH INCLUDES THE RECOVERY OF THE SXT AFTER THE POINTING PROBLEMS. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday 24-Aug-98 12:01 1 980824 P1 ARS1 SPECIAL ******* Monday 24-Aug-98 15:26 3 980824 P3 ARS1 STD Tuesday 25-Aug-98 10:37 1 980825 P1 ARS0 WSF Tuesday 25-Aug-98 14:01 3 980825 P3 ARS1 DARKCAL Wednesday 26-Aug-98 10:53 1 980826 P1 ARS1 STD Wednesday 26-Aug-98 14:18 3 980826 P3 ARS1 STD DIF Thursday 27-Aug-98 12:53 2 980827 P2 ARS1 STD Friday 28-Aug-98 09:46 1 980828 P1 ARS1 STD Saturday 29-Aug-98 11:44 2 980829 P2 ARS1 STD Note that this plan may change during the week. Orbit precession means that we have table naming confusion again - the convention is, the UT date of pass #1 determines the SXT table ID. 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.