SXT REPORT FROM ISAS 22 June 94 to 12 July 94 J. R. Lemen SOLAR ACTIVITY Solar activity has maintained steady low level for the past three weeks at about the GOES B level. There have been at two more active regions on the disk at any time. Two M-class flares observed by GOES during this time. The rise phase and peak of an M2.5 flare was observed by Yohkoh on 30 June 1994 at about 21:00 from AR 7742. The other M flare occurred on 7 July 1994 during Yohkoh's local night. AR 7742 also produced at least one C flare and numerous B flares. PEOPLE This has been a very busy time as far as visitors to ISAS are concerned. Several arrived for the Solar-B meeting that was held at ISAS last week. They included: S. Antiochos (NRL), R. Canfield (U. of Hawaii), J. L. Culhane (MSSL), J. Davis (MSFC), K. Dere (NRL), G. Doschek (NRL), L. Golub (SAO), J. Harvey (NSO), W. Kalkofen (NASA), W. Lites (HAO), J. Owens (MSFC), A. Title (Lockheed) and W. Wagner (NASA). During this time Nariaki Nitta arrived for a three-week visit to attend the Solar-B meeting, work with Lidea van Driel and prepare for Cospar. Sam Freeland arrived for a one-month stay. We said good bye to Lidia van Driel, as she and her family will be moving to France new week. The other locals at ISAS included B. LaBonte, L. Murnion, A. Sterling, H. Hudson, B. Handy, M. Kundu, and J. Lemen. OPERATIONS SXT operations continue to go smoothly. Brian Handy has now taken over as the SXT Chief Observer, having mastered all the intricacies of the FACOM mainframe computers. Lemen stands by as advisor and backup Chief Observer. We are taking a breather from campaigns at the moment. Last week we lost part of one day's data because there was a problem with the antenna at KSC. We are beginning to loose about one KSC pass a week because of conflicts with the Japanese ASCA mission. The orbits to ASCA and Yohkoh are nearly the same. The conflicts will continue to get worse over the next few months before ASCA starts to get ahead of Yohkoh. Freeland, Nitta and Lemen investigated the composite images that were being sent to the daily forecast centers. The appearance of these images had degraded with decreasing solar activity. The reason was discovered in the software that prepared the images. The software has been modified and improved composite images are now being regularly distributed. Freeland also increased the cadence of images being delivered to Selsis to help predict the observation of large-scale activity such as that observed on 14 April 1994. RESEARCH ITEMS During the Solar-B meeting there were some opportunities to discuss various scientific projects. Canfield and Hudson met with Kurokawa to discuss the data acquired during last month's campaign involving Yohkoh and Hida Observatory. Two good examples of emerging flux regions observed X-rays have been noted and will be studied in more detail. LaBonte has been hard at work analyzing the SXT dark signal images. His work has concentrated on the long exposures since the details of the dark current subtract become very important when analyzing faint features in the long (say, 30 sec) exposures. He has discovered that there are three secular terms in the morphology of the dark current levels. There is an overall increase that has been observed in the dark currents can be approximated by a quadratic function. However, there is also a strong orbital trend that has been recently also noticed by Acton. In particular, the dark images taken in the first ten minutes of the orbit appear to have dark signals that are a few DN higher than later in the orbit. The investigation of this is not complete, but we think it might be related to the length of the UV flood interval. Finally, there is another trend that seems to be correlated with the times of the CCD bake outs. We are using a new dark calibration sequence to try to obtain better data for this study. Handy has developed a program to analyze this data. LaBonte will complete his analysis soon and is working on a report. We expect that we will be able to improve the dark subtraction software for the case of long exposures. The Masuda "home run" event paper has been accepted for publication. Lidia van Driel and Hudson worked on white flares. With improved software, they have found several more good examples.