SXT Status Report 27 September - 10 October 1999 (Weeks 40-41) B. Handy, H. Hudson, D. McKenzie SUMMARY Activity during this two-week reporting period continued a long streak of underwhelming activity, with a handful of mid C-class flares and baseline activity in the mid-B level. SXT participated in one observing campaign (SOHO JOP 103, "Coronal Moss"), and we continued exploring sequences to observe the large-scale loops connecting active regions across the solar equator. SOLAR ACTIVITY The first half of the reporting period was ominously quiet, with few flares of any sort to report. The latter half was slightly more interesting with a number of mildly flaring active regions appearing from over the east limb. We speculate wildly that solar activity is in some sort of a local minimum. OBSERVING CAMPAIGNS Yohkoh/SXT participated in JOP 103 ("Moss") in collaboration with La Palma, TRACE, MDI, CDS and SUMER on 6-7 October. Please see our Web pages for full information regarding past and future campaign plans: 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 No outstanding issues at the moment. We continue to work with the stray light database, in an attempt to understand how to better select suitable terminator images. Hugh Hudson conjectured that the best terminators will occur when Yohkoh is passing over the terminator at an angle as far from normal incidence as possible, which would mean a larger window for collecting suitable terminators. SXT OBSERVING SEQUENCE TABLES ------------------------------------------------------------- UT Date & Time Pass Table ID ============================================================= 27-SEP-99 14:13 1 990927 P1 ARS1 DIFFUSER 27-SEP-99 19:19 4 990927 P4 ARS1 STD 28-SEP-99 12:45 1 990928 P1 ARS1 IL 28-SEP-99 16:08 3 990928 P3 ARS1 DARK 29-SEP-99 12:58 1 990929 P1 ARS0 IL 29-SEP-99 18:04 4 990929 P4 ARS1 STD 30-SEP-99 16:36 3 990930 P2 ARS0 IL 30-SEP-99 20:01 5 990930 P5 ARS1 STD 05-OCT-99 14:18 3 991005 P3 ARS1 DARK 06-OCT-99 14:32 4 991006 P1 ARS0 LAPALMA 06-OCT-99 14:32 4 991006 P3 ARS1 DIFFUSER 06-OCT-99 14:32 4 991006 P4 ARS0 IL 07-OCT-99 09:38 1 991007 P1 ARS1 STD 08-OCT-99 11:34 3 991008 P3 ARS1 STD 09-OCT-99 10:05 2 991009 P2 ARS0 IL 09-OCT-99 11:47 3 991009 P3 ARS1 STD ============================================================= SCIENCE During this reporting period, we found that any attempt to study interconnecting loops was a virtual guarantee that none would exist in the field of view. We have sharpened our strategies for studying such loops, and with a better understanding of how best to observe these structures this study will in due time be expanded to include TRACE and other observatories. The following weekly science nuggets were produced. 08-Oct-99: A Long-Lived Dark Loop 01-Oct-99: The SXT Data Trail 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 30 September: G. Vekstein (NAO; Manchester University) "Plasma Heating by Magnetic Reconnection" YOHKOH OPERATIONS ISSUES No special issues at present. PERSONNEL Phil Shirts arrived from Palo Alto. Brian Handy returned to Bozeman. David McKenzie arrived from Bozeman. TOHBANS (spacecraft operators) Tohbans for week 40 SSOC: M. Hagino, J. I. Khan KSC: Y. Saitoh, M. Nishio SXT_CO: B. Handy SXT_SW: P. Shirts Tohbans for week 41 SSOC: D. Sasaki, Te. Watanabe KSC: Y. Saitoh, Y. Katsukawa SXT_CO: B. Handy, D. McKenzie SXT_SW: P. Shirts