A1POINT ivo://nasa.heasarc/a1point NASA/GSFC HEASARC NRL; HEASARC 2026-06-19 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Lightcurve HEAO 1 (High Energy Astronomical Observatory) is a spinning survey mission X-ray satellite. It launched 12 August 1977 and was in operation until 9 January 1979. HEAO-1 rotated once per 30 minutes about the Earth-Sun line. In this manner, the instruments scanned a great circle in the sky that lay 90 degrees from the sun. A given source near the ecliptic was viewed for a few days while sources near the ecliptic pole were scanned nearly continuously during the entire mission. The satellite has limited pointing capability that was used to produce this data, giving continuous coverage of selected sources. The pointings began about 100 days into the mission. The A1 instrument, also known as the NRL Large Area Sky Survey Experiment (LASS) covered the energy range 0.25 to 25.0 keV. The experiment consisted of seven detectors, six mounted on the -Y side of the spacecraft, the seventh on the +Y side. Two detectors, with a FWHM of 1 deg x 0.5 deg and open area of 1350 cm2 were tilted a third of a degree either towards or away from the Z (Sun-pointed) four other -Y side detectors has a FWHM of 1 deg x 4 deg and an open area of 1650 cm2. The single +Y detector has a FWHM of 2 deg x 8 deg and an open area of 1900 cm2. The experiment had sufficient sensitivity to detect sources as faint as as 0.25 uJy at 5 keV for sources with a Crab-like spectrum. Data was collected in either a 5 or a 320 millisecond timing resolution mode: Full sky coverage for both time resolutions was achieved before the mission's end. Wood et al. (1984) discuss the experiment and a catalog of sources in further detail. This is a service provided by NASA HEASARC . https://heasarc.gsfc.nasa.gov/W3Browse/all/a1point.html Archive Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=a1point& GET text/xml 180 99999 true 128.4 -45.05 0.5 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=a1point GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_a1point&Action=More+Options&Action=Parameter+Search&ConeAdd=1 HEAO1 0.5 X-ray public a1point HEAO 1 A1 Lightcurves name Target Designation meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable "time" Observation Start Time mjd time.start;obs double nullable end_time Observation Stop Time mjd time.end;obs double nullable mjfstart Major Frame of Observation Start time;obs.param int nullable mjfstop Major Frame of Observation Stop time.end;obs.param int nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable lii Galactic Longitude degree pos.galactic.lon double nullable exposure Time on Source (seconds) s time.duration;obs.exposure double nullable bii Galactic Latitude degree pos.galactic.lat double nullable obs_id Observation Identifier meta.id;obs char nullable telapse Length of This Observation (seconds) s time.duration;obs double nullable class Browse Object Classification src.class short nullable file_lcurve FITS Lightcurve File Name meta.dataset;meta.file;phot char nullable