The data from the Hard X-ray Imaging Spectrometer (HXIS) consist of solar flare images in X-rays, built up from simultaneous photon counting rates in each of 6 energy bands with boundaries at 3.5, 5.5, 8.0, 11.5, 16, 22, and 30 keV, from each of 432 contiguous square regions of the Sun. Solar flares were the instrument's target, but observations were also made during quiet times. The instrument ... operated from SMM launch date, 1980 Feb. 14, through 1980 Nov. 22. The instrument's field of view was approximately square and 384 arc-sec on a side. The full area was covered by 128 pixels each 32 arc-sec on a side, known as the coarse field of view. The central part of the coarse field of view was covered with 304 pixels each 8 arc-sec on a side, which made up the fine field of view. At the start of a flare, the time resolution was 1.5 s; after a pre-programed time (a few minutes) the resolution was changed to 4.0 s; and after another pre-programed interval it was changed to 7.5 s. The resolution remained 7.5 s during quiet times. When the instrument operated in its 1.5-s time resolution mode, telemetry restrictions cut short the data reporting from some of the pixels; counts in the pixels were reported in order of decreasing number until time ran out.
Selected active regions on the Sun were tracked according to a flare patrol program which was revised daily. The instrument's coarse field of corresponded closely to the size of a typical active region. The target active region was tracked continuously, except for coverage gaps during satellite night (about 30 minutes of night every 96 min), and during passage through the South Atlantic Anomaly.
Originally the data were stored on about 900 raw data tapes at 1600 bpi. The raw data tapes were copied onto Exabyte tape cartridges at the Solar Data Analysis Center at NASA/GSFC for a permanent archive. Data segments of special interest, including the brightest flares, were collected in a smaller set of 76 tapes known as HIMSEL tapes. Copies of these data products exist at the Lab. for Space Research, Utrecht, the Netherlands, at the University of Birmingham, in the United Kingdom, and at the Solar Data Analysis Center in the U.S.A.. Data analysis software and documentation are available at those sites. At Birmingham, there is also an additional set of HIMSEL tapes, containing more data segments of special interest. A copy of the first 76 HIMSEL tapes is held at the Applied Physics Lab.
Additional associated data sets: The on-line event list and flares of GOES magnitude larger than M observed with HXIS are integrated in an on-line catalog of flares which was based on the HXRBS catalog. Part of this catalog is being published in a series of NASA Technical Memoranda. Numerous data sets of selected data are held by Co-Investigator groups. Movies of 250 HXIS flares also were made in 16mm format by D.M. Rust and D.A. Batchelor; these are at The Johns Hopkins University Applied Physics Laboratory.
Some users's guide documentation exists, but close contact with the PI team or SMM Data Analysis Center personnel is necessary for correct results. Limited numbers of data requests can be processed at the Solar Data Analysis Center. Some additional data can be obtained via collaborative projects with PI's and Co-I's. Advice on use of the HXIS software and data at the Solar Data Analysis Center can be obtained from Paul Hick (PHick@solar, CASS01::PLHCME CASS01=27.131) or Dave Batchelor at NSSDC.