SXT Status Report May 1, 2000, to May 14, 2000 (Weeks 19-20) H. Hudson, B. Handy SUMMARY Activity was low and high (lopsided-Sun syndrome); we supported JOP120; SXT has had no technical problems. SOLAR ACTIVITY There were nine M flares in this interval. The growth of the sunspot regions on the disk was quite spectacular (8996 grew a factor of three in area in one day), and two bright regions with accompanying TILs were appearing over the E limb at the weekend. OBSERVING CAMPAIGNS Yohkoh supported SOHO JOP120 on network flares. The observations on Saturday and Sunday were probably of no value, but those of Monday may have been satisfactory. The exposure times to see network flares were too long, even though the Sun providentially went through its deepest mini-minimum in a while, so we probably won't schedule quiet-Sun observations in the near future again. 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 Hudson completed the first step in studying Yohkoh jitter at full time resolution for the IRU readouts. It does not look dangerous to the software or databases! The next step won't happen until June. The Canopus sensor STT was off between May 2 and May 9 because of celestial constraints - this happens regularly. Accordingly the Yohkoh roll stability and pointing will have suffered during this interval. SXT OBSERVING SEQUENCE TABLES ------------------------------------------------------------- UT Date & Time Pass Table ID ============================================================= Monday PM 01-MAY-00 10:15 4 000501 P3 ARS1 DKCAL Tuesday PM 02-MAY-00 07:00 2 000502 P2 ARS1 DIF Tuesday PM 02-MAY-00 10:24 4 000502 P4 ARS1 JOP 83 Wednesday PM 03-MAY-00 07:09 2 000503 P2 ARS2 JOP 83 Thursday PM 04-MAY-00 07:14 2 000504 P2 ARS1 JOP 83 Friday PM 05-MAY-00 07:19 2 000505 P2 ARS1 JOP 83 Saturday PM 06-MAY-00 08:13 4 000506 P4 ARS1 STD Monday PM 08-MAY-00 02:50 1 000508 P1 ARS1 DKCAL Monday PM 08-MAY-00 07:56 4 000508 P4 ARS0 JOP122 Tuesday PM 09-MAY-00 06:23 3 000509 P3 ARS1 DIF Wednesday PM 10-MAY-00 01:27 1 000510 P1 ARS1 RAPID Thursday PM 11-MAY-00 03:18 2 000511 P2 ARS1 RAPID Friday PM 12-MAY-00 05:09 3 000512 P3 ARS1 RAPID Saturday PM 13-MAY-00 05:19 4 000513 P4 ARS1 STD ============================================================ Data reformatting is complete through May 6, 2000 - amazingly current! Yohkoh may have finally lost Santiago coverage: e-mail from Debbie Dukes, the Wallops contact person, says that they are no longer scheduling us. However, providentially, the KSC situation is getting better because of ASCA's rapid orbital decay (see the science nugget advertised below), but our reduction in data coverage from this will still be in the 10-20% range. SCIENCE Seminars: none scheduled. Science Nuggets 28-Apr-00: "Running in circles", the first bit of Brian's handiwork on characterizing the Yohkoh orbital decay. The bottom line is that this series of science nuggets may become quite long... 05-May-00: "Another nice but accidental discovery", a nugget that describes a remarkable evolution in trans-equatorial loops. It involves (shh..) _reconnection_ as a likely explanation! The structure looks similar to a well-known TRACE image of a knotty feature at the top of a loop. Our speculation here is that mass-loading drove the reconnection. 12-May-00: "Fandango from an X-class flare - we think", here "fandango" refers to a Mexican dance, and Mexico refers to the date of the flare, May 5. The source region was far around the limb, so we think that the flare was really X-class; out from behind the limb we spotted pirouetting flux ropes. Sort of, well, a kind of fandango? 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 . PERSONNEL B. Handy departed and returned. G. Slater and N. Nitta arrived. TOHBANS (spacecraft operators) Tohbans for week 19 SSOC: L. Bargatze, K. Hori KSC: S. Morita, T. Miyagoshi SXT_CO: B. Handy, H. Hudson SXT_SW: - Tohbans for week 20 SSOC: K. Shibasaki, T. Kobayashi KSC: T. Morimoto, T. Miyagoshi SXT_CO: H. Hudson SXT_SW: G. Slater