SXT Status Report 25 October - 6 November 1999 (Weeks 44-45) L. Fletcher, H. Hudson, D. McKenzie SUMMARY Activity was low-to-moderate, ending the period with a spectacular LDE event at the NW limb, following ominous Sac Peak warnings of yellow-line emissions there. SXT and Yohkoh continued to work well. SOLAR ACTIVITY There were nine M flares, mostly from a compact region (8749) at S18. Come to think of it, active-region latitudes already appear to be lower. Can a butterfly flap its wings this fast? The most spectacular event of the interval was either the nuggetized event of October 26 (a "Masuda event"? - see the nugget for week 44) or the spectacular limb arcade event happening as this report gets written. A future nugget, perhaps. OBSERVING CAMPAIGNS During week 44, the special flare campaign (highly successful, apparently, in increasing the number of TRACE + Yohkoh events) continued under the name of JOP 113. We also supported the resurrection of JOP 104, begun in May 1999, as SUMER entered high telemetry mode in an attempt to observe Doppler shifts during eruptive events (like flares and jets). Believe we increased the number of flares jointly observed by SUMER, SXT, and TRACE, plus numerous GBOs. As an informal campaign we attempted to get special observations related to NS interconnecting loops, hoping of course for a TILDE (trans-equatorial interconnecting loop disappearance event), as happened during the flares of May 1998. Some of this material is summarized in the nugget for week 45. Please see our webpages for more details about campaigns past and future: http://isass1.solar.isas.ac.jp/sxt_co/sxt_catalog.html http://isass1.solar.isas.ac.jp/sxt_co/sxt_future.html SXT INSTRUMENT STATUS AND CALIBRATION ACTIVITIES A normal pointing update was made on 3-Nov-99. The flare trigger remains at its older (low) level through this interval, and the flare-mode sequence table aiming at high cadence remained in place. This table takes one Q res, one H res, and six F res images per cycle of nominally 16 sec. After changing the FLARE ARS image setup to Thick Al/Open, DPE=11, pointing during flare sequences has been quite good, with no new instances of flare PFIs being targeted at the southeast margin of the CCD. SXT_COs should keep an eye on this. As of 06-Nov-99, no new NaBan straylight monitor images have displayed the saturation bleed mentioned in the previous SXT Status Report. This may be as a result of the increase in CCD flushing implemented on 25-Oct, but we should keep an eye on it. By Chief Observer error, considerable PFI data with AEC disabled were obtained, mostly on AR8749. The exposures were probably a factor of 4 too long - not enough to cause damage, but long enough to provide an interesting view of fainter loops in the AR. We mention this because such data sets are rare. AR8749 in fact had a great deal of outer-loop activity. The flares tended to be compact, but the large-scale structures participated. Final data reformatting is complete through October 24. In week 46 we will lose 16 KSC contact passes, more than half, due to overbooking of the KSC telemetry system. This makes special operations (such as bakeout) quite difficult. SXT OBSERVING SEQUENCE TABLES ------------------------------------------------------------- UT Date & Time Pass Table ID ============================================================= Monday 25-OCT-99 05:05 3 991025 P3 ARS2 FLARE SPEC Tuesday 26-OCT-99 00:11 1 991026 P1 ARS2 DARK+FLARE Wednesday 27-OCT-99 02:06 2 991027 P2 ARS0 FLARE SPEC Wednesday 27-OCT-99 05:31 4 991027 P4 ARS2 FLARE SPEC Thursday 27-OCT-99 22:55 1 991027 P1 ARS0 FLARE SPEC Thursday 28-OCT-99 02:19 3 991027 P3 ARS2 FLARE SPEC Friday 29-OCT-99 02:32 3 991029 P3 ARS2 FLARE SPEC Saturday 29-OCT-99 21:40 1 991029 P1 ARS0 FLARE SPEC Saturday 30-OCT-99 01:03 3 991029 P3 ARS1 STD Monday 31-OCT-99 22:05 1 991031 P1 ARS2 DIFF+J104 Tuesday 01-NOV-99 20:37 1 991101 P1 ARS1 DARKCAL Wednesday 02-NOV-99 22:32 2 991102 P2 ARS0 STD+IL Wednesday 03-NOV-99 01:57 4 991102 P4 ARS1 STD Thursday 03-NOV-99 21:03 1 991103 P1 ARS0 STD+IL Thursday 04-NOV-99 00:27 3 991103 P3 ARS1 STD Friday 04-NOV-99 21:16 2 991104 P2 ARS1 STD Saturday 05-NOV-99 19:47 1 991105 P1 ARS1 STD ============================================================= SCIENCE The weekly science nuggets: 5-Nov-99: A TIL Fades Slowly into the West This deals with the trans-equatorial loop observations, and provides links to the several earlier nuggets on related topics. 29-Oct-99: A splendid limb flare An event destined to be studied extensively - a Masuda flare. The full list of nuggets is kept on http://isass1.solar.isas.ac.jp/sxt_co/index.html , and the current week's nugget also normally resides on http://isass1.solar.isas.ac.jp/sxt_co/SXTweekly.html . SEMINARS October 28: Title: "Stochastic Modelling of (Flare) Particle Transport and Acceleration" Speaker: L. Fletcher (LMSAL) YOHKOH OPERATIONS ISSUES 1.) Keep an eye on the NaBan straylight monitor images (FFI#1, entry 2-2, Op/NB Dark QC1N) to see if the saturation bleed from the bottom of the CCD goes away after 25-oct, when the flush was increased from 4/1/1 to F/2/3. (As of 06-Nov-99, no new NaBan images have shown the saturation bleed mentioned above. Keep an eye on this.) 2.) It's been three months since our last bakeout. We are now entering the dark phase of the orbit precession (ie, KSC at night during contact passes) which is unfavorable for bake operations. But we are losing so many passes to ASCA it will be very difficult. 3.) Mercury transit is 15-Nov; Leonids meteor shower is 18-Nov. Soon! PERSONNEL Lyndsay Fletcher returned to Palo Alto; Hugh Hudson returned to ISAS; Dick Canfield arrived to be tohban. TOHBANS (spacecraft operators) Tohbans for week 44 SSOC: T. Takahashi, S. Akiyama KSC: M. Shimojo, T. Shimizu SXT_CO: L. Fletcher, D. McKenzie SXT_SW: - Tohbans for week 45 SSOC: H. Nakajima, D. Canfield KSC: T. Shimizu, M. Yamaguchi SXT_CO: D. McKenzie, H. Hudson SXT_SW: -