Page 1 PROGRESS REPORT THE SOLAR-A SOFT X-RAY TELESCOPE (SXT) PROGRAM (CONTRACT NAS8-40801) (for Octomber 1996) OVERVIEW The YOHKOH Mission is a program of the Japanese Institute of Space and Astronautical Science (ISAS) with collaboration by the U. S. National Aeronautics and Space Administration and the U. K. Science and Engineering Research Council. The YOHKOH satellite was launched on 30 August 1991 from Kagoshima Space Center (KSC) in Japan. The purpose of this mission is to study high energy phenomena in solar flares and the Sun's corona. 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 at the Lockheed Palo Alto Research Laboratory in cooperation with the National Astronomical Observatory of Japan, and the Institute for Astronomy of the University of Tokyo. MAJOR PROGRAMMATIC ACTIVITIES IN THE MONTH Operations and data analysis are continuing in their normal mode. The expectation is that Option 2 to continue operations for CY 97 will be implemented in November. Frank Friedlaender attended the 47th International Astronautics Federation Congress where he had an opportunity to disseminate the value of both Yohkoh and the Yohkoh Public Outreach activities to a very broad audience as well as distribute the mini-posters and the Yohkoh business cards. << Solar Activity >> The solar activity continued to be dominated by the fifth rotation of the old AR 7978, which produced a splendid CME event on 5 October (see the report under Campaigns below). During the other times the disk was mostly covered with bright points and faint emission. There are polar holes at both poles. << Campaigns >> Several SOHO-related campaigns of scientific interest to Yohkoh took place, including JOP03 (CME onset), JOP33 (jets), and observations aimed at loop structure. The JOP33 was led by Lyndsay Fletcher from the SOHO EOF. During this time Jim Lemen was the EIT science planner, so it worked out well from the point of coordinating the observing strategy with Yohkoh/SXT. The ideal scenario for JOP-033 would be to have Yohkoh identify an Page 2 emerging-flux region or the appropriately jet-active part of an existing AR, and then let SOHO know the location in nearly real time. This is not an easy job, and the first attempts produced no results. We hope eventually to catch a jet and apply the SOHO spectroscopic instruments to understanding the physical conditions. As for CMEs, this reporting interval produced a beautiful set observation on 5 October. Alas neither this nor the 25 September CME were observed during the JOP programs, although, EIT has good observations of the 5 October CME event. Nevertheless there were excellent synoptic observations, and because the 5 October event occurred in the faint remnants of the isolated active region that we have been watching, the SXT partial-frame images were making long exposures at full resolution during the eruption. The resulting movie is spectacular, and a comparison of the low-corona structures SXT sees with the full CME development seen by LASCO should be extremely informative. These two events are the first for which we know that we have simultaneous Yohkoh and SOHO observations of CMEs, and the low level of solar activity seems to be a help since the X-ray signatures may be quite faint. The SERTS rocket flight is currently planned for November 13, 1996 and the New Brunswick rocket may also fly during November. For Yohkoh operations, there is a text file accessible on the Web at http://www.space.lockheed.com/SXT/html2/First_Light.html which also lists the current SXT Chief Observer, or the unix command: # finger campaign@isass0.solar.isas.ac.jp | more The SOHO target planning is available from: http://sohowww.nascom.nasa.gov/operations/targets/today << Science >> David Alexander quickly settled into to his new position. He is working on multiple HXT analysis projects. One involves the comparison of the HXT emission with the non-thermal Ca XIX velocity. Khan et al (1996) pointed to a possible correlation between these. He also worked with Tom Metcalf to study footpoint occultation of HXT limb flare events using model electron spectra and HXT imaging data. David is also working to organize the HXT CDAW which will be held in January. Jim Lemen spent 2.5 weeks on the east coast and was the EIT science planner for two weeks. Tom Metcalf took over as the EIT science planner after that. It was a good opportunity to learn about the SOHO operations and to discuss Yohkoh collaborations and operations with various SOHO co-investigators. Tom Metcalf continued to work with G. Fisher and D. Longcope on the SOHO mini campaign comparing SoHO and SXT image with photospheric vector magnetograms. The project's goal is to study transient brightenings. While at GSFC, he got updated pointing Page 3 for the CDS data which he is aligning with SXT and IVM data. Nariaki Nitta continues his work on superhot flares. It appears that superhot temperatures (from Fe XXVI) occur in flares with a very soft hard X-ray spectrum, but morphology varies and many of such flares are highly localized, not allowing good temperature measurement by SXT (saturation, scattered light...). He revised the paper on one superhot flare that was submitted in September. Nariaki also continued his search for hard X-ray signatures from microflares, using GOES and HXT-L light curves and SXT images. These microflares do not look much different from larger flares in terms of the relation between hard X-ray time-integrated and soft X-ray peak fluxes. Those microflares with relatively high soft X-rays but without hard X-ray signatures are found to involve more than one structures or some large-scale loops. A draft paper is being written on the results. Jean-Pierre Wuelser ended his month-long visit to ISAS on October 4. While there, he made modifications to the ATT file generation software (see calibration below). In response to Wuelser's SPD poster on vector magnetic field observations of near-polar fields (with Don Mickey), Zoran Mikic expressed his strong interest in such measurements. He is an expert in global magnetic field extrapolations into the corona, and pointed out that one of the main problems is the lack of good observations of the (vertical) field near the poles. High sensitivity transverse field observations would be extremely valuable for global field extrapolations. The IVM at Mees Solar Observatory has the potential of filling that gap. Greg Slater spent the month at ISAS. Part of the time he was preparing for his talk at the Yoyogi meeting and he also worked (remotely) with Gary Linford on various data base and reformatting issues. Gary is continuing to re-organize the data bases on the ISAS computers so that there is greater redundancy in case of computer problems. Gary worked on the CD-ROM juke box installation at LMPARL and he has been working on a new Yohkoh video with help from Strong and Alexander. << Public Use of SXT Images >> We are continuing to make Yohkoh/SXT images available for a variety of uses. Efforts continue to make selected images available on the Lockheed SXT WWW homepage (http://www.space.lockheed.com/SXT/). We receive requests for the Yohkoh posters (#2 and #3) by way of the form on the SXT homepage. Currently we receive requests via our homepage at the rate of 2 or 3 per day. The WEB access statistics in September were 42949 accesses and 982 Mbytes transferred. Work continues on the fifth anniversary briefing package and on a new video with will concentrate on solar connections. << Yohkoh Operations and Health >> Yohkoh and the SXT continue to function very well. There has been no Page 4 further increase in straylight since 25 August 1996. The quiet patrol image has been changed to Al/Mg (DPE=17) to try to improve the performance of the active region selection algorithm for times when the Sun is very quiet. SXT conducted a one-day bakeout, which was scheduled between the many SOHO joint observing programs Yohkoh is involved with. This was the first bakeout since February, 1996. The warm status of the CCD gives a better look at the dark signal and therefore any degradation. The gradual increase of dark signal noted previously has continued, but there also appear to have been areas of annealing behavior. The CCD basically looks healthy. The gradual degradation of the signal levels of both HXA sensors (X slightly faster than Y) caused software problems for SXT image registration over the last few months, as described in the last report. The HXT team has now increased the gain on the HXA-X sensor output, and Jean-Pierre Wuelser has updated his alignment software to handle the degradation. At the time of writing the fix is in place and database reconstruction for the missed interval is under way. The HXA problem is a gradual one, and may in a year or two require additional steps, so we will try to monitor the HXA outputs more regularly in the future. This is not the only way to calibrate the Yohkoh gyros for fine pointing, but it is the easiest and probably the best. SXT experienced a normal level of Single Event Upset (SEU) events during the month: SXT bit map 4-Oct-96 Pass 5: 961004-0723 recovered in same pass. SXT write error 28-Oct-96 Pass ?: 961028-1342 recovered in next pass. Caused by operations error. Page 5 << Data Flow >> ------------------------------------------------------------------------------ Month Full Frame Images Observing Region Images Received Lost Received Lost Loss % QT FL Tot Thru Jul-94 231252 104023 1007178 314087 1321265 519539 27.88 Aug-94 7370 2337 35067 3993 39060 13485 25.66 Sep-94 7079 2552 25131 2855 27986 10677 27.62 Oct-94 7244 2497 25868 5884 31752 10319 24.53 Nov-94 6569 1941 26243 1956 28199 9293 24.79 Dec-94 6429 2456 26763 2583 29346 11904 28.86 Jan-95 6870 2349 26103 1699 27802 10211 26.86 Feb-95 6556 2545 23635 3825 27460 10111 26.91 Mar-95 5915 2082 21485 3448 24933 8485 25.39 Apr-95 6244 2266 22946 4493 27439 9688 26.09 May-95 7084 2884 29617 2647 32264 15331 32.21 Jun-95 7210 3087 25251 307 25558 12045 32.03 Jul-95 6418 4145 21180 1639 22819 15109 39.84 Aug-95 7683 2597 26115 2181 28296 10537 27.13 Sep-95 6546 2853 22006 1753 23759 10433 30.51 Oct-95 6937 3502 22177 3853 26030 13044 33.38 Nov-95 5745 2944 21252 517 21769 12119 35.76 Dec-95 6163 2615 24059 901 24960 11652 31.83 Jan-96 6474 2530 27015 1708 28723 14151 33.01 Feb-96 6200 2581 21380 890 22270 10773 32.60 Mar-96 6908 2869 25437 1460 26897 12274 31.33 Apr-96 7172 2124 45445 671 46116 18848 29.01 May-96 6925 2426 30272 1089 31361 12367 28.28 Jun-96 7522 2716 31984 1536 33520 14489 30.18 Jul-96 5954 1995 29886 4769 34655 12427 26.39 Aug-96 7214 3010 21187 1607 22794 9887 30.25 Sep-96 6904 2618 29906 303 30209 12663 29.54 Oct-96 2820 1153 7769 1120 8889 3898 30.48 Nov-96 0 0 0 0 0 0 0.00 Total 409407 173697 1702357 373774 2076131 835759 28.70 Number of Full Frame Images Received: 409407 Number of Observing Region Images Received: 2076131 Total: 2485538 Approximate Number of Shutter Moves/CCD Readouts: 4341278 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 << Engineering Summary Table >> -------------------------------------------------------------------------------- Month Avg Dark Level # of Dark Spikes CCD Warmings Front Optical (DN) (e/sec) Over 48 Over 64 High / # Support Trans Temp /Days Temp (%) Aug-94 46.98 617.6 57624 4050 25.2 / 3 18.2 N/A Sep-94 47.07 620.9 58580 4028 18.3 N/A Oct-94 47.34 631.3 64974 4346 19.0 N/A Nov-94 47.64 642.4 70877 4703 20.4 N/A Dec-94 47.82 649.1 74246 4917 21.5 N/A Jan-95 48.55 676.7 89758 5457 20.0 N/A Feb-95 48.70 682.1 92457 5781 25.2 / 3 20.5 N/A Mar-95 48.35 668.9 85527 5271 19.4 N/A Apr-95 48.72 682.8 93904 5627 19.1 N/A May-95 48.73 683.4 94000 5820 18.8 N/A Jun-95 49.08 696.3 100780 6281 19.6 N/A Jul-95 49.34 706.2 106408 6628 18.1 N/A Aug-95 49.72 720.4 114414 7101 19.5 N/A Sep-95 49.79 723.1 115165 7222 19.6 N/A Oct-95 50.29 741.9 126452 7911 20.2 N/A Nov-95 50.11 735.1 122163 7814 25.2 / 2 20.3 N/A Dec-95 50.19 737.9 123705 7927 22.6 N/A Jan-96 50.81 761.3 136197 8888 21.5 N/A Feb-96 50.67 755.8 133263 8705 22.5 / 2 21.5 N/A Mar-96 50.85 762.9 136982 8973 20.3 N/A Apr-96 51.14 773.6 142250 9500 19.9 N/A May-96 51.16 774.4 140697 10018 19.1 N/A Jun-96 51.56 789.2 147705 10634 20.7 N/A Jul-96 57.45 1010.2 146293 12228 19.8 N/A Aug-96 52.58 827.5 165676 12393 19.6 N/A Sep-96 52.47 823.3 162784 12350 20.0 N/A Oct-96 52.30 817.0 158619 12308 22.5 / 2 20.7 N/A Nov-96 N/A N/A N/A N/A 0.0 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 Foreign Travel between 1-OCT-96 and 31-OCT-96 ACTON 6-OCT-96 31-OCT-96 * 26 (total of 26 days) HUDSON 1-OCT-96 31-OCT-96 * 31 (total of 31 days) SAVY 1-OCT-96 * 31-OCT-96 * 31 (total of 31 days) SLATER 1-OCT-96 31-OCT-96 * 31 (total of 31 days) WUELSER 1-OCT-96 * 4-OCT-96 4 (total of 4 days) ---------------------------------------------------------------- Grand Total of 123 days for 5 people NOTE: The "*" signifies travel that actually ends after 31-OCT-96 SXT Foreign Travel between 1-NOV-96 and 30-NOV-96 ACTON 1-NOV-96 * 5-NOV-96 5 (total of 5 days) HUDSON 1-NOV-96 * 5-NOV-96 5 9-NOV-96 18-NOV-96 10 25-NOV-96 30-NOV-96 * 6 (total of 21 days) NITTA 9-NOV-96 30-NOV-96 * 22 (total of 22 days) SAVY 1-NOV-96 * 30-NOV-96 * 30 (total of 30 days) SLATER 1-NOV-96 * 5-NOV-96 5 9-NOV-96 15-NOV-96 7 (total of 12 days) WEBER 20-NOV-96 30-NOV-96 * 11 (total of 11 days) ---------------------------------------------------------------- Grand Total of 101 days for 6 people NOTE: The "*" signifies travel that actually ends after 30-NOV-96 Respectfully submitted, James R. Lemen Frank M. Friedlaender Page 8 ------------------------------------------------------------------------------- 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 | 10 November 1996 October 1996 |------------------------------- | 6. PERFORMING ORG | CODE: O/91-30 -----------------------------------------------|------------------------------- 7. AUTHOR(S) | 8. PERFORMING ORGANIZA- J. R. Lemen | 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 - 40801 -----------------------------------------------|------------------------------- 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 October 1996 |------------------------------- |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 | 8 | ------------------------|------------------------|-----------------|----------- For sale by: Superintendent of Documents, U.S. Government Printing Office