19 April 1998 Nariaki Nitta SXT CHIEF OBSERVER'S REPORT AND TABLE PLAN CHIEF OBSERVER'S REPORT for Week 16 13-Apr-98 to 19-Apr-98 SOLAR ACTIVITY Solar activity continued to be low to medium with the GOES background level staying in the B2-B4 range. The large active region complex including AR 8194 stayed quiet and moved toward the southwest limb, where it finally showed a large-scale expansion (between 17-Apr-98 23 UT and 18-Apr-98 06 UT). On the southeast limb, an eruptive event was seen from the back side on 16-Apr-98 at 04 UT. On the northern side, AR 8203 grew rapidly on 15-Apr-98 and reached the level of producing four high C-class flares in 20 hours. But the growth appeared to stop. SXT INSTRUMENT STATUS After the full recovery from last week's error on Monday, SXT has been working fine. 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 Barbara Thompson returned to GSFC, after familiarizing workers at ISAS with beautiful EIT movies. SEMINARS The Yohkoh seminar resumed on Thursday (16 April). The speaker was Huaning Wang (Beijing Observatory & NAOJ) and the title was "Magnetic separatrices and solar atmospheric heating in an active region" There was a visit by Takashi Tachibana, a leading journalist, who is remembered as revealing a major political scandal in the 1970s. SXT TABLE PLAN FOR WEEK 98_17 (20-Apr-98 - 26-Apr-98) SXT Chief Observer: Hudson No special observations are planned at the moment, and below are just routine tables. But if solar conditions are favorable, we may run special sequences, e.g., for jet hunting. Note that this plan is subject to change. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday 20-APR-98 06:33 4 980420 P4 ARS1 STD Tuesday 21-APR-98 05:08 4 980421 P4 DARKCAL Wednesday 22-APR-98 03:43 3 980422 P3 ARS1 DIFF Thursday 23-APR-98 00:36 2 980422 P2 ARS1 STD Friday 24-APR-98 04:19 4 980423 P4 ARS1 STD Saturday 25-APR-98 01:11 3 980424 P3 ARS1 STD Note: the day number of the table ID is based on the UT of pass #1 in the KSC sequence for that day. So don't be alarmed by two 980422's. 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.