CHIEF OBSERVER'S REPORT for Week 42 9-Oct-00 through 15-Oct-00 A. Takeda, B. Handy, D. McKenzie GENERAL Solar activity was generally low this week, except that the NOAA9182 produced a M1.5 flare on 12 Oct UT, and an M1.1 on 14 Oct, both near the northwest limb. SXT TECHNICAL Yohkoh lost lock on Canopus this week and the instrument rolled approximately 30 degrees before the trend was stopped. The causes of this anomaly are still being investigated, but the S/C has reacquired Canopus and we are again in fine sunpoint. To prevent damage to the CCD during large pointing displacements, SXT was halted during the worst of the pointing drift, and ran FFI-only tables with short exposures (to facilitate an independent check of the pointing) until the situation was cleared up. For the balance of the week SXT has been running a standard table. SXT emerged from this week unscathed. SXT SCIENTIFIC For Web material see the science nuggets: Current Week: http://isass1.solar.isas.ac.jp/sxt_co/001013.html Index: http://isass1.solar.isas.ac.jp/sxt_co/index.html The latest nugget looks at the repeated brightening of coronal loops surrounding a filament channel, as observed in EUV and soft X-rays in January 2000. CAMPAIGNS JOP 104 continues, though because of (1) more activity elsewhere and (2) pointing difficulties, we have been a non-participant. B. Schmeider's Flare campaign (JOP131) ended on 15th Oct. 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 Hudson left on the 13th and Handy the 14th. McKenzie arrived on the 13th. Schmieder visited after the S-RAMP meeting to look at data from TRACE and Yohkoh taken during the Flare Genesis flight. SEMINARS No seminar this week, but instead we had a small meeting in the D-toh coffee room for general informal discussion based on presentations people had at S-RAMP or the Astronomical Society meeting. Volunteers were Schmieder, Glover, and Hudson. TELEMETRY DOWNLINKS Week Wallops Goldstone Canberra Madrid NASA Japan 42 19 2 1 0 22 33 43 30 0 0 10 40 32 SXT TABLE PLAN, WEEK 43 (16-Oct-00 to 21-Oct-00) JOP104 continues until 27th Oct., but we may not actively cooperate with the campaign unless there is a more promising region coming up on the east limb than regions elsewhere. Two table uploads are planned for Wednesday morning, 18-Oct. Because of power suspension expected on 21th at Sagamihara, the operation holiday this week is set on Saturday. We thus upload a table on Sunday AM JST. ________________________________#_______________________________ JST Day UT Start Time Pass Table ID Monday AM 16-Oct-00 00:26 3 001016 P3 ARS1 DIF Tuesday AM 17-Oct-00 00:32 3 001017 P3 ARS1 STD Wednesday AM 17-Oct-00 19:33 1 001017 P1 ARS1 DARK* Wednesday AM 18-Oct-00 00:38 4 001018 P4 ARS1 STD Thursday AM 18-Oct-00 23:02 3 001018 P3 ARS1 STD* Friday AM 19-Oct-00 21:26 3 001019 P3 ARS1 STD* Sunday AM 21-Oct-00 19:55 2 001021 P2 ARS1 STD* * means that the UT date of pass 1 differs from the JST date of the pass in question This table plan is subject to change. Continuing requests: KSC & SSOC Tohbans: If any KSC passes are likely to be cancelled (for example due to heavy snowfall) 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, 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. < Appendix > ----------------------------------------------------- The status of ASCA (from ISASnews #234, October 2000) ----------------------------------------------------- The X-ray astrophysical satellite ASCA remains out of control. This is because of the heavy magnetic storm occurred on July 15th, which significantly perturbed the spacecraft attitude. Although we are continuing with efforts to regain control, it does not seem likely that we will succeed. Since its launch in February, 1993, ASCA had successfully observed many objects, yielding about 950 papers in refereed journals and over 70 doctoral theses. In July of this year, unfortunately, the altitude of the satellite at apogee had decreased to 440 km from its initial value of 530 km. From this fact, we still expected that we could continue observations for a year or so until reentry. However, a huge solar flare occurred on July 14th, followed by a major geomagnetic storm on July 15th. As the result, the density of the Earth's atmosphere in the ASCA orbit suddenly increased to a level several times its usual level. This resulted in a disturbance to the satellite via drag to such a degree that ASCA could no longer maintain its attitude. The satellite automatically dropped into its safe-hold mode, but this too was insufficient because of the unexpectedly heavy drag. ASCA continued to drift into an attitude where the solar panels could not receive sufficient solar radiation. The battery eventually drained, leaving ASCA in its present state, out of control. In order to recover the satellite, the first thing to do would be to supply power to the battery and resume the safe-hold mode. But the battery has been heavily damaged by its severe discharge and it has proved difficult to restore charge. We are now studying the power system intensively, but the problem seems intractable in the short term. Tadayasu Dotani (translated by TA and HSH)