Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-37334) (for the month of August, 1993) OVERVIEW The SOLAR-A Mission is a program of the Institute of Space and Astronautical Science (ISAS), the Japanese agency for scientific space activity. The SOLAR-A satellite was launched on August 30, 1991 from Kagoshima Space Center (KSC) in Japan, and renamed Yohkoh. The purpose of this mission is to study high energy phenomena in solar flares. Under an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation using the Soft X-ray Telescope (SXT), one of the primary experiments of the mission. The SXT was developed by Lockheed in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR ACTIVITIES IN THE MONTH << Solar Activity and Observation Planning >> August 31 was the two year anniversary of the launch of Yohkoh. The telescope is in remarkably excellent condition for solar observing after nearly 2 years in orbit. The level of scattered light has not changed since November '92 and radiation damage to the CCD accumulates much more slowly than anticipated. The reason for this good fortune is under study. It may be intrinsic or may be the UV flood-- probably some of each. SXT mechanisms, electronics, and temperature are stable. Contamination continues to accumulate on the CCD (believed to be water ice) and is removed by periodic heat-up of the CCD to about 20 C. At this point Yohkoh and SXT can anticipate a long and productive life as a space solar observatory. Yohkoh weathered the storm of the Perseid meteor shower without effect. The x-ray sun continues to evolve towards quieter conditions. In August one flare reached the M category but generally the GOES level was around the B1 level. One side of the sun was essentially covered with quiet corona with only small coronal holes. The other side of the sun had very large coronal holes. Even at the low level the x-ray pictures are full of detail and non-potential structures. A new SXT observing sequence with fixed long and short exposures is being used in order to increase the dynamic range of the SXT movie by forming composite images. This technique appears to be quite successful and is giving better coverage of the fainter active region features than we have had before. Page 2 << Campaigns >> The Emerging Flux Region campaign with the Germans at Tenerife, the Lockheed team at LaPalma and several other observatories in Japan and around the world began on 3-Aug-93 and continued through 13-Aug-93. Observations in Japan were hampered by unseasonably poor weather but a few promising joint data sets were acquired. The Solar EUV Rocket Telescope and Spectrograph (SERTS) Rocket Launch occurred on 18-Aug. SXT images provided by FTP to the launch site at White Sands were used in planning the targeting and observing program of this GSFC rocket experiment. The rocket launched exactly on time and the special SXT observing sequence succeeded perfectly. This should be a very valuable data set for studying the chromosphere/corona interface. << Data Analysis Software >> A modified version of SXT_PREP (temporarily called SXT_PREP2) is being tested for pre-processing of the SXT data. The routine will perform alignment (correcting for S/C jitter and optionally correcting for solar rotation), flag the saturated pixels, calculated the uncertainty for each pixel, perform dark current and leak image subtraction, and exposure normalization. The routine will work on PFI, FFI, or a combination. In the near future, the routine will perform temporal interpolation, spatial re-binning, and de-spiking. Freeland refined remote SW upgrade procedures which maintain parallel software versions at Lockheed and Montana, using isass0 as the master software source. The Yohkoh software and selected Yohkoh data base areas at these two sites are automatically updated every 24 hours via the internet and the system is extensible to other hosts. The backup SW systems at ISAS and LPARL were also upgraded to take advantage of these refined procedures. In addition, portions of the automatic Yohkoh data base update system were made machine independent and implemented directly on the ISAS backup system. This will allow the Yohkoh Science observers/planners access to an uninterrupted flow of data from ground based, Yohkoh, GOES in the event that the primary server goes down. Developed remote SW upgrade system for 'non-trusted host' sites using an anonymous ftp account. When complete, this will allow remote sites running Yohkoh software to remain current within 24 hours of the version on the ISAS master. This system provides an alternative to the one described in the preceding paragraph; in this case, the initiation of the upgrade request is from the remote site and not from ISAS. Protections on the anonymous ftp account will assure that only software (and not Yohkoh data) may be accessed in this way. The installation software (UNIX script files) automatically registers remote installers and verifies that execution times will not adversely impact the ISAS network. This system uses an single, incremental (compressed tar) file to minimize impact on the network. Page 3 << Instrument Operations and Health >> The typhoons in southern Japan caused some problems, the least of which was problems with the phone lines and getting observing sequence FAX reports down to KSC. Between 3-Sep and 7-Sep the typhoon shut down all operations for Yohkoh which will result in a 3 day gap in the solar movie. SXT has refined the procedure for trying to get terminator images. It now uses on board timer (OP/OG) but the resolution of the command timing is still very coarse which causes more than 50% misses. Diffuser images made 3-Aug-92 were examined to learn the status of x-ray damage. There has not been an alarming change but enough new radiation damage has been accumulated, especially at the NE limb that Yohkoh should be repointed a couple of arcminutes to move the limbs to a fresh area on the CCD. This was done 10=Aug-93. Special "sunset" images are being acquired both with and without the x-ray neutral density filter for calibration and correction purposes. It was discovered that use of the neutral density filter greatly increases the straylight signal, although the effect on flare observations is minor (and correctable) because the exposures are so short. There were SXT Bit Map Errors on the following days (with a full recovery during the same pass or the next pass): 930818-1240 930819-1444 There was an SXT Warm Error on 930820-1341 which was recovered on the following pass. The CCD was baked out for 2 days ending on 24-August in order to remove contaminants which had deposited on the CCD. This operation is performed every 2-3 months and there were no problems during this operation. The number of S/C offpoints in August was reduced because of problems with typhoons and conflicts with observing campaigns. There was an 8 arcminute offpoint east and west on 26-August. In late August, it was noticed that there were several occasions when the SXT PFI was mis-pointed. Upon further study it was discovered that the mis-points occurred during times when the Yohkoh was transiting the SAA. Since the flux from the active regions has decreased so much, the automatic region selection software is sometimes fooled by cosmic rays, which are now competing in signal strength under certain circumstances. This is only a minor problem and the time of mis-pointing lasts no more than ten minutes, which is the interval between patrol images. Page 4 << Data Flow >> Due to problems in getting the data for one dump to DSN, the distribution of data fell behind. We will catch up in the next few days, and at that time we will re-process some older weeks (since the earlier reformatter version had some errors). There are only about 12 old weeks to be re-processed before we have all data up to an acceptable reformatter version. << Papers and Conferences >> Linford is in the process of establishing a network link to give Sky and Telescope an SXT image a month for a new feature that will perhaps be called "Solar Weather" which will include a short summary of solar activity for the past month and a note worthy image of the month. Most of the SXT team members spent the latter part of August preparing for the Kofu Science Meeting. The papers presented at that meeting will be discussed in the September report. Page 5 << Engineering Summary Table >> Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Sep-91 517 397 21174 3541 24715 5481 18.15 Oct-91 4106 2532 6393 12437 18830 3401 15.30 Nov-91 5291 2475 12149 14696 26845 10952 28.98 Dec-91 4858 3228 4983 16837 21820 6910 24.05 Jan-92 5544 3177 10084 5972 16056 6849 29.90 Feb-92 5305 2803 16932 11382 28314 12019 29.80 Mar-92 5910 2699 19236 2653 21889 10589 32.60 Apr-92 6751 3483 20157 5423 25580 12327 32.52 May-92 7032 3158 25464 4589 30053 13745 31.38 Jun-92 6417 3632 21648 12725 34373 14782 30.07 Jul-92 6345 3275 23941 10510 34451 14717 29.93 Aug-92 6572 2978 24207 11154 35361 13550 27.70 Sep-92 6087 2916 26832 20042 46874 15729 25.12 Oct-92 6743 2589 50985 14709 65694 23687 26.50 Nov-92 6658 2939 24416 14696 39112 12924 24.84 Dec-92 6775 2999 24253 6633 30886 12356 28.57 Jan-93 6888 3351 24067 4861 28928 13069 31.12 Feb-93 6833 3004 24479 18149 42628 12302 22.40 Mar-93 7177 3460 25874 19537 45411 14657 24.40 Apr-93 7754 3644 34128 8352 42480 17967 29.72 May-93 8571 3950 41832 7518 49350 21971 30.81 Jun-93 7340 2589 64545 12539 77084 26299 25.44 Jul-93 8259 3650 47561 5352 52913 24213 31.39 Aug-93 3320 1574 15998 1938 17936 9084 33.62 Total 147053 70502 611338 246245 857583 329580 27.76 Number of Full Frame Images Received: 147053 Number of Observing Region Images Received: 857583 Total: 1004636 Approximate Number of Shutter Moves/CCD Readouts: 1766936 NOTES: * The loss of images is mainly due to BDR overwrites, but there are also occasional DSN dumps which are lost. * It is common to have observing regions which contain more than 64 lines, which requires multiple exposures to make a single observing region image. This is why the number of shutter moves is larger than the number of images received plus those lost. Page 6 Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) Oct-91 31.07 21.3 509 261 10.5 77.8 Nov-91 31.06 20.9 648 277 11.9 64.4 Dec-91 31.04 20.2 804 353 14.0 52.5 Jan-92 31.13 23.6 985 450 0.5 / 2 14.9 38.4 Feb-92 31.32 30.8 1176 544 14.3 31.7 Mar-92 31.47 36.5 1355 626 14.8 25.1 Apr-92 31.44 35.2 1323 610 23.8 / 4 14.6 22.8 May-92 31.65 43.1 1417 653 14.4 20.1 Jun-92 32.12 60.9 2215 880 -2.5 / 3 15.1 17.4 Jul-92 32.22 64.4 1852 832 15.5 14.1 Aug-92 32.21 64.1 1922 886 14.9 13.1 Sep-92 32.38 70.5 2062 954 -1.2 / 3 15.9 12.2 Oct-92 32.64 80.3 2317 1055 16.8 11.5 Nov-92 36.24 215.1 6112 1391 18.0 11.0 Dec-92 42.58 452.8 17390 2024 17.9 N/A Jan-93 42.59 453.1 13006 2034 23.8 / 2 19.2 N/A Feb-93 42.28 441.5 13895 2090 17.7 N/A Mar-93 43.14 473.8 14047 2151 17.7 N/A Apr-93 43.13 473.4 14304 2146 23.8 / 2 16.9 N/A May-93 43.45 485.3 16405 2357 17.3 N/A Jun-93 44.03 507.2 20037 2531 16.3 N/A Jul-93 44.52 525.6 23977 2700 22.5 / 2 17.7 N/A Aug-93 44.00 505.8 20050 2638 17.0 N/A NOTES: * The dark current calculations are using full half resolution 2.668 sec images not taken in during the SAA. The dark current rate assumes a "fat zero" of 30.5 DN and a gain of 100 e/DN. * The entrance filter failure of 13-Nov-92 eliminated the capability of taking optical images, so the optical transmission is not available after Nov-92. It also caused an increase in the dark current signal, however some of the increase shown here is an increase in the readout noise and is not a function of exposure duration. Page 7 << Personnel Travel >> SXT travel for the month of August, 1993: ACTON 1-AUG-93 * 21-AUG-93 21 (total of 21 days) FREELAND 23-AUG-93 31-AUG-93 * 9 (total of 9 days) HUDSON 1-AUG-93 * 31-AUG-93 * 31 (total of 31 days) LEMEN 24-AUG-93 31-AUG-93 * 8 (total of 8 days) NITTA 1-AUG-93 * 5-AUG-93 5 (total of 5 days) SLATER 1-AUG-93 * 31-AUG-93 * 31 (total of 31 days) STRONG 27-AUG-93 31-AUG-93 * 5 (total of 5 days) Grand Total of 110 days for 7 people Planned SXT travel for the month of September, 1993: FREELAND 1-SEP-93 * 24-SEP-93 24 (total of 24 days) HUDSON 1-SEP-93 * 15-SEP-93 15 (total of 15 days) LEMEN 1-SEP-93 * 21-SEP-93 21 28-SEP-93 30-SEP-93 * 3 (total of 24 days) MORRISON 27-SEP-93 30-SEP-93 * 4 (total of 4 days) SLATER 1-SEP-93 * 15-SEP-93 15 (total of 15 days) STRONG 1-SEP-93 * 12-SEP-93 12 (total of 12 days) Grand Total of 94 days for 6 people Respectfully submitted, Mons D. Morrison Frank Friedlaender Page 8 -------------------------------------------------------------------------------- UNIVERSITY OF HAWAII ACTIVITY REPORT (DR. R. CANFIELD) Our most important activities included support of Yohkoh operations and data analysis at ISAS, coordinated ground-based data acquisition at Mees, collaborative analysis of Yohkoh/Mees data, preparation of papers for publication, and presentation of papers at meetings (notably, the SPD meeting at Stanford, at which numerous papers were presented). During this period operational support for SXT was provided by Hudson and LaBonte at ISAS, Judd, Nitta, and Douglass at Mees, and Canfield, Jiao, Leka, Metcalf, Mickey, and Wuelser in Manoa. Solar activity was generally low. New postdocs Gianna Cauzzi (from Arcetri) and Aleksei Pevtsov from Irkutsk arrived. Jeff de la Boujardiere departed at the end of this interval for his new position at Meudon, but not until completing his paper on the non-eruptive two-ribbon flare of 24 October 1991, one of the subject flares of the first Hawaii Coordinated Data Analysis Workshops. The second Hawaii Coordinated Data Analysis Workshop, on the topic of "Magnetic Flux Emergence and Flares in NOAA AR 7260", which will be held at the Institute for Astronomy, University of Hawaii, November 30 to December 3, 1993. The scientific organizers are T. Sakurai and R. Canfield. With Acton and Reardon, Canfield worked on preflare X-ray and optical phenomena associated with the 1991 Nov 15 flare. Canfield gave a paper entitled "Filament Tether Cutting Before a Major Eruptive Flare" at the Stanford meeting of the Solar Physics Division of the American Astronomical Society. Canfield also worked with Nishio and Metcalf to provide magnetograms for Nishio's analysis of the 1992 June 28 flare and with Shibasaki and Leka to provide magnetograms for Shibasaki's analysis of AR 7260's radio and X-ray emission. Metcalf worked with Mickey on the initial analysis of the IVM H-alpha flare data. In particular I co-aligned the Yohkoh SXT and and HXT data with the IVM data for the October 27, 1992 flare. He also worked with Andrzej Fludra to generate figures incorporating Mees Stokes data and SXT data for the 23 June 1992 and 13 July 1992 flares. Litao Jiao picked 9 loops in an active region from the SXT images from August 1992 and found the most correlated magnetograms for these loops from Mees. These have been co-registered to make overlays, and maps of vertical current with the 180-degree ambiguity have been generated. After slightly modifying the J. A. Klimchuk's code, he applied it to the 9 loops and measured the width of an X-ray loop as a function of position along the loop axis. This led to several interesting findings: a)If the vertical current densities at 2 footpoints of the loop are strong, i.e,above 3 sigma level (which can be computed from the magnetograms), the constancy of the width along the loop axis is higher than for loops that have one end in strong vertical current density but weak in the other (less than 3 sigma), especially, the widths are very much likely to approach each other at the ends. Page 9 b)If the current density at one footpoint is lower (<3 sigma) and the other is larger ( > 3 sigma ), generally the width is greater at the end with lower current density. Wuelser spent the month of July at ISAS. During the first two weeks of his stay he supported the SXT operations as a SXT chief observer. He also worked with Morrison on upgrading the Yohkoh pointing database and software. During the period of the report, Wuelser worked on three research projects. In collaboration with Nitta he analyzed MCCD data in the context of flares and emerging flux in AR 7260. Wuelser and Rolli combined Swiss Ca-H and H-epsilon imaging spectroscopy data with Yohkoh data for two flares on January 5, 1992 and August 20, 1992. Rolli is visiting from Bern (Switzerland) where he obtained the imaging spectroscopy observations as part of his thesis work. Finally, Wuelser continued to analyze a set of three large flares in the context of energy transport, chromospheric heating, and chromospheric evaporation. Wuelser finished the assembly and the testing of the new Mees White Light Telescope (MWLT). The MWLT was installed and aligned, and started taking observations on August 25. The MWLT serves to more accurately co-register Mees and Yohkoh data after the failure of the SXT aspect telescope. It's a 1317 x 1035 pixel digital CCD system that replaces its standard video predecessor. Hudson submitted the final version of the "soft X-ray footpoints" paper, after presenting this material at the SPD meeting. He worked on analysis of Yohkoh coronal data, including estimates of temperature and mass in an X-ray CME event observed on 23 June 1993, for which Mauna Loa data may also be available. During July and August, Leka prepared for the Solar Physics Division meeting where she presented a poster on the Emergence of Twisted Flux Tubes. She will give an oral presentation at the Sacremento Peak observatory Summer Workshop on a similar topic at the end of August. She continues to prepare two manuscripts concerning AR 7260, and hopes to submit them at the end of September. After that she will continue to work with IVM data to obtain a second dataset for her thesis, and also to calibrate the magnetic data obtained by this instrument. Mickey cleaned up the IVM data reduction routines and installed them on the new Sparc-10 at Mees. The observers are now producing quick-look magnetograms within an hour of their acquisition, normally for the first active region survey of the day. These magnetograms tend to underestimate the field strengths, and there are still one or two optical artifacts which are troublesome, but the full active region coverage with 1.1 arcsecond pixel size is an improvement over the Polarimeter data. The IVM shutter electronics was modified to reduce radiated noise which was getting into the image stabilizer circuits. Page 10 PLANS FOR SEPTEMBER AND OCTOBER Several of the Hawaii staff (Metcalf, Wuelser, Hudson, Leka) will attend the Kofu meeting in September. This is the first major international meeting devoted to Yohkoh and Nobeyama data, and the Mees observations are a key part of several of the data analyses to be reported. The second annual Hawaii Coordinated Data Analysis Workshop, mentioned above, will take place at the end of this period. Because this workshop deals with subject matter that is very appropriate for Mees and Yohkoh, i.e. active-region development, many of the Hawaii personnel will be busy with preparations. Canfield plans to work on tether cutting before the 1991 Nov 15 flare. This is a new theoretical concept that may help to explain the eruption of the filament seen before the onset of that flare. Metcalf plans to submit his paper on AR6952 that shows the lack of any correlation between x-ray brightness and photospheric currents. He also will write up a study (with Jiao) on the height dependence of the magnetic field using a combination of Na-D and FeI magnetograph data. He will continue the analysis of the IVM H-alpha data on the polarization signature of non-thermal particles. Jiao intends to do further quantitative data analysis of Mees magnetograms in the context of SXT images. The IVM will continue generating daily magnetograms, several per day on each region with spots but increase cadence for complex or developing regions. Track down and eliminate, if possible, the ghost images. Mickey will investigate the calibration in the magnetic field analysis routines, by study of the Stokes profiles and comparison with Polarimeter data. We will make quick-look magnetograms more available, probably by means of hard-copy maps of the center of the field. Hudson will give a review paper at the Kofu meeting, and intends to emphasize the SXT soft X-ray observations of the corona then. He is working with Lemen and Acton in interpretation of the outer corona, and (he hopes) with D. Sime of HAO on interpretation of the 23 June transient. He will generate software to model coronal brightness distributions based upon Withbroe models, and perhaps this will be useful also for the Spartan intercomparisons. Finally, he intends to pursue microflares observed by SXT in its "PFI-dominant" mode of high time resolution in conjunction with MCCD data. This should enable a test of the hypothesis that the small end of the event size spectrum may differ in its energetics (H-alpha vs. soft X-rays) relative to real flares. Page 11 -------------------------------------------------------------------------------- UNIVERSITY OF CALIFORNIA AT BERKELEY The paper on the temperature and density the 2-November-91 flare has been accepted by the Astrophysical Journal Letters, and will be published in the Oct. 20, 1993 issue. Results from the comparison of Yohkoh WBS data with Ulysses and PVO data for the 15-Nov-91 flare were presented by J.McTiernan at the SPD meeting which took place at Stanford from July 13-16. McTiernan will present the same poster at the "New Look at the Sun" Symposium in Kofu, Japan from September 6-10. Work on spectral fitting is continuing; spatially resolved SXT and HXT spectral fitting routines are available in the yohkoh software directories, called sxtbox_fsp.pro and hxtbox_fsp.pro. These treat the SXT filter exposures as if they were spectrometer channels, in order to combine with HXT to obtain thermal-nonthermal spectra. For aligned combinations of images from the two detectors, the program sxthxtbox_fsp.pro will give spatially resolved SXT-HXT spectra. This program is still being tested, to remove bugs. The spatially resolved HXT spectra are being used to compare with thick-target electron beam models, and will also prove useful in searching for the low energy cutoff of the nonthermal hard X-ray spectrum. Page 12 -------------------------------------------------------------------------------- STANFORD UNIVERSITY (DR. P. STURROCK) In July, our entire group attended the Solar Physics Division Meeting, held at Stanford. Jim Klimchuk gave a talk entitle "A Comparison of Coronal Temperatures and Emission Measures Determined from X-Ray and Microwave Observations" (coauthored by Dale Gary of Caltech). The work is concerned with of soft X-ray data from SXT and microwave data from the Owens Valley Radio Observatory. We find that X-ray temperatures and emission measures are systematically larger than microwave temperatures and emission measures. This can be explained by a coronal temperature that decreases with height. After the SPD meeting, Klimchuk was visited by Dave Webb of AFGL to discuss their collaboration on coronal mass ejections. The group was also visited by Ron Moore and Jason Porter of MSFC. Klimchuk helped Porter with a temperature and emission measure analysis of the microflare he is studying. The comparison of X-ray and microwave data mentioned above was for NOAA Active Region 6891. Klimchuk has recently started to work on a second active region, NOAA 7128, which is simpler and therefore better suited to this type of study (this is in collaboration with Jeremy Lim of Caltech). Lisa Porter and Klimchuk have analyzed 25 coronal loops observed by SXT to determine the relationship between loop pressure and loop length. For static loops, this relationship indicates the dependence of loop heating and loop length, which places important constraints on theories of coronal heating. During the next two months, Klimchuk and Porter will continue there analysis of loop pressures and lengths, and Klimchuk will write up his work on NOAA 6891. Peter Sturrock and George Roumeliotis will attend the Kofu Symposium. Page 13 -------------------------------------------------------------------------------- SOLAR PHYSICS RESEARCH CORPORATION (KAREN L. HARVEY) Activity these last two months has focussed on several areas: (1) continued work on the collaborative observing program between SXT/Yohkoh and the NSO/KP magnetograph of XBPs on 9-10 December 1993 and the more recent data collected during 17-21 May 1993. Initial results from an analysis of the high temporal and spatial resolution PFI observations of approximately 50 XBPs and the coordinated magnetic field observations were presented at the 13-16 July 1993 Solar Physics Division meeting to be held at Stanford University and at the 13th Summer Workshop held at the National Solar Observatory/Sacramento Peak 31 August - 3 September 1993. Analysis of these data continues with the objective of a paper to be submitted for publication within the next few months and for presentation at the next SPD meeting to be held with the AGU next spring. (2) continued update of bibliography of SXT/Yohkoh papers; the bibliography is being restructured for easier access as per conversation with N. Nitta. (2) continuation of plans for multi-observatory collaborative observing programs to study X-ray bright points. The next opportunity for a collaboration will present itself in early October. Plans are to contact the Chief Observer in Japan to arrange the collaboration pending low solar activity and then to arrange the observing run with National Solar Observatory/Kitt Peak, Big Bear Solar Observatory, and Mees Solar Observatory. Observatories in Japan and in China also will be contacted for participating. Page 14 -------------------------------------------------------------------------------- MONTANA STATE UNIVERSITY (LOREN ACTON) GENERAL During the past bimester work has been divided amongst PI-type activities, a period as SXT Chief Observer at ISAS, and work on some science papers. All planned activities listed in the last report from MSU have been accomplished except for hardware ordering which is still in work. Mr. Brian Handy, a graduate student in Physics at MSU, has accepted a position as Research Assistant on the Yohkoh program. Brian has passed his PhD. comprehensive examinations and intends to do his doctoral dissertation on SXT data. He is presently helping me with the hardware procurement and working up a talk on coronal heating for his MSU oral exam requirement. Dr. David Alexander has deferred his arrival until the first of November. During the period I gave four talks in which SXT results were included: 7/28 Rotary Club, Billings, MT 8/05 Yohkoh science seminar at ISAS, Japan 8/24 University convocation at Bozeman, MT 8/25 Channel 7 (ABC) news interview, Bozeman, MT CHIEF OBSERVER ACTIVITY AT ISAS (3-20 August 1993) OPERATIONS 1. Emerging Flux Region Campaign (led by T. Sakurai) 3-13 Aug '93. This 10 day campaign suffered from poor conditions at the ground observatories. Coordination was successful and some data were obtained. 2. Solar EUV Rocket Telescope and Spectrograph (SERTS) Rocket Launch. SXT images provided by FTP to the launch site at White Sands were used in planning the targeting for this GSFC rocket experiment. The rocket launched exactly on time and the special SXT observing sequence succeeded perfectly. The SERTS experimenters report 100% success. 3. Calibration activities: 3.1 CCD x-ray damage. Discovered that negative deviations in the SLD dark images is directly related to x-ray (over)exposure and that they recover with a time constant of about a week. I now believe that deviations in the SLS straylight images may be related to the accumulation and annealing of x-ray damage. 3.2 Optical diffuser images. Based upon accumulated x-ray damage decided to repoint Yohkoh 2 arcmin west and 0.5 arcmin south. 3.3 Straylight contamination with the 8% mask. Acquired calibration data to correct for this effect. 3.4 Straylight/pinhole correction for Al.1 images. Acquired and analyzed data. Algorithm for correction still in work. 3.5 CCD gain calibration. Ran an experiment to attempt this calibration. 3.6 X-ray scattering experiment. Failed--no flares. Page 15 SXT STATUS The telescope is in excellent condition for solar observing after 2 years in orbit. The level of stray light has not changed since November '92 and radiation damage to the CCD accumulates much more slowly than anticipated. SXT mechanisms, electronics, and temperature are stable. Contamination continues to accumulate on the CCD (believed to be water ice) and is removed by periodic heat-up of the CCD to about 20 C. Yohkoh and SXT should have a long and productive life as a space solar observatory. NEW PROGRAMS PUT ON LINE PFI_COMPOSITE for making movies of composite pfi images. BLS_SHIFTER to shift the images taken with BLS ON to the right. SUNSETS to test sunset images for proper x-ray cleanliness. SLD_VSTRIPS to page through the SLD data base to inspect individual vertical strips on the CCD for radiation damage effects. PLOT_SLD should be run first to get the data. DUSTOFF is a program to interpolate out the 2 big dust specks on HR images. This is used by sxt_diffuser2. SXT_DIFFUSER2 to create a flattened diffuser image from a pair of Lo8 and Compressed half-resolution diffuser images. CENTRUP to extract, print out and return the HXA suncenter coordinates. SCIENTIFIC WORK I commented on the draft of a paper by Hara and provided the UH group with the conversion of DN in an SXT image to luminosity on the sun. (This program has now been released for general use.) Work on the paper on the General Corona for IAU Colloquium #144 proceeded by fits and starts and was the subject of the seminar at ISAS. The Annual Reviews paper with Sturrock on coronal heating has been delayed for a year. The Sky&Telescope article appeared and turned out very well. We owe thanks to Carol Peterson who wrote it and Strong and Roethig for help with the illustrations. Work with Fuller and Lemen on the WSMR calibration work continues. Good progress has been made and a definitive answer for location, on the CCD, of the x-ray optical axis of SXT has been derived. A considerable amount of time was spent on issues connected with the public release of the first year of Yohkoh data at the SDAC at Goddard and on the establishment of an FTP account for the posting of a daily SXT image at CRL in Hiraiso, Japan. PLANS FOR NEXT REPORTING PERIOD - Complete ordering of computer and video hardware for MSU. - Present paper at IAU Colloquium 144 in Slovak Republic. - Derive correction algorithm for Al.1 "pinhole" straylight. - Keep current on SXT/Yohkoh operations and interact as required. - Visit LPARL the week of 11 October 1993. Page 16 -------------------------------------------------------------------------------- NASA REPORT DOCUMENTATION PAGE (IN LIEU OF NASA FORM 1626) --------------------|--------------------------|-------------------------------- 1. REPORT NO. | 2. GOVERNMENT | 3. RECIPIENT'S DR-01 | ACCESSION NO. | CATALOG NO. --------------------|--------------------------|-------------------------------- 4. TITLE AND SUBTITLE | 5. REPORT DATE Monthly progress report - for the month of | September 10, 1993 August 1993 |-------------------------------- | 6. PERFORMING ORGANIZATION | CODE: O/91-30 -----------------------------------------------|-------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- M. D. Morrison | TION REPORT NO: F. M. Friedlaender | |-------------------------------- -----------------------------------------------|10. WORK UNIT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS | Lockheed Palo Alto Research Labs B/252 |-------------------------------- Solar & Astrophysics Laboratory O/91-30 |11. CONTRACT OR GRANT NO. 3251 Hanover Street, Palo Alto Ca. 94304 | NAS8 - 37334 -----------------------------------------------|-------------------------------- 12. SPONSORING AGENCY NAME AND ADDRESS |13. TYPE OF REPORT AND Marshall Space Flight Center (Explorer Program)| PERIOD COVERED Huntsville Alabama 35812 | Progress report for the month | of August, 1993 |-------------------------------- |14. SPONSORING AGENCY | CODE MSFC / AP32 -----------------------------------------------|-------------------------------- 15. SUPPLEMENTARY NOTES -------------------------------------------------------------------------------- 16. ABSTRACT The SOLAR-A Mission is a program of the Institute of Space and Astronautical Science (ISAS), the Japanese agency for scientific space activity. The SOLAR-A satellite was launched on August 30, 1991 to study high energy phenomena in solar flares. As an international cooperative agreement, Lockheed, under NASA contract, is providing a scientific investigation and has prepared the Soft X-ray Telescope (SXT), one of the two primary experiments of the mission. --------------------------------------|----------------------------------------- 17. KEY WORDS (SUGGESTED BY | 18. DISTRIBUTION STATEMENT AUTHOR(S)) Solar-A, X-ray, CCD, | Space Science, Solar Physics ------------------------|-------------|----------|-----------------|------------ 19. SECURITY CLASSIF. | 20. SECURITY CLASSIF. | 21. NO OF PAGES |22. PRICE (OF THIS REPORT) | (OF THIS PAGE) | | None | None | 16 | ------------------------|------------------------|-----------------|------------ For sale by: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001