24 April 1998 Hugh Hudson SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN CHIEF OBSERVER'S REPORT for Week 17 19-Apr-98 to 26-Apr-98 SOLAR ACTIVITY Solar activity was generally low, but there were major proton flares on April 20 (over the W limb) and April 24 (over the E limb). The biggest sunspot group was 8205, at about 100. SXT INSTRUMENT STATUS SXT has been working fine. We experimented a bit with a "monochromatic" movie table, ie deleting all Al.1 images. This FFI ran for about four days (until the end of the 22nd), but I personally think it's not the right thing to do (Aurass and I had just been measuring densities in discrete large-scale structures - can't do that with one filter!). The flare table was pushed to higher cadence in H and Q resolution, just in time for the April 24 X flare. This therefore has extremely well-observed ejecta. It also has two-filter observations, in good cadence, if anybody is brave enough to want to attempt a temperature analysis. This is a job for an expert, I think. 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 CAMPAIGNS There were no formal campaigns this week. PERSONNEL Dick Canfield arrived. Barbara Thompson and Henry Aurass departed. SEMINARS No seminar this week, sorry. SXT TABLE PLAN FOR WEEK 98_18 (27-Apr-98 - 3-May-98) SXT Chief Observer: McKenzie At the end of this week we will try to run the Clette high time resolution program. Details are TBD, but some of the tables listed below aim at that. Note that this plan is subject to change. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday 27-APR-98 01:47 4 980426 P4 DARKCAL Tuesday 27-APR-98 22:39 4 980427 P2 ARS1 DIFF Wednesday 29-APR-98 00:40 3 980428 P3 ARS1 STD Thursday 29-APR-98 21:32 2 980429 P2 ARS2 FAST Thursday 30-APR-98 00:58 4 980429 P4 ARS1 STD Friday 30-May-98 18:26 1 980430 P1 ARS2 FAST Friday 30-May-98 21:50 3 980430 P3 ARS1 STD Saturday 1-May-98 22:08 3 980501 P3 ARS1 STD Continuing requests: 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 & 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). 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.