- ID:
- ivo://nasa.heasarc/ariel5
- Title:
- Ariel V All-Sky Monitor
- Short Name:
- ARIEL5
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The All Sky Monitor was one of six X-ray instruments on the Ariel 5 satellite. The satellite was launched into a low inclination (2.8 degrees), nearly circular orbit (altitude ~520 km) on 15 October 1974. Ariel 5 was actively pointed so that objects of interest could be observed by the four instruments aligned along its spin axis. The ASM was mounted 90 degrees from the spin axis; the satellite had a spin period of 6 seconds. The ASM operated from October 18, 1974 to March 10, 1980. The ASM instrument, built by the Lab for High Energy Astrophysics at NASA- Goddard Space Flight Center, provided continuous coverage of the entire sky, except for a 20 degree band straddling the satellite's equator. The ASM was intended to act as an early detection system for transients, and to monitor the variability of bright ( > 0.2 Crab) galactic sources. The instrument consisted of a pair of X-ray pinhole cameras, each covering opposite halves of the sky, with gas-filled imaging proportional counters. Position determination of sources was accomplished through position-sensitive anode wires and satellite rotation. Each camera had a 1-cm<sup>2</sup> aperture. Overall telemetry constraints limited the duty cycle for any given source to 1 percent. With the low telemetry rate provided for this instrument (1 bit/s), temporal and spectral information were sacrificed for the sake of all-sky coverage. Hence, spectral information was limited to a single 3 - 6 keV bandpass, and temporal resolution was limited to the satellite orbital period, ~100 minutes. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/a1point
- Title:
- HEAO 1 A1 Lightcurves
- Short Name:
- A1POINT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://nasa.heasarc/a2lcpoint
- Title:
- HEAO 1 A2 Pointed Lightcurves
- Short Name:
- A2LCPOINT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The A2 experiment was flown on the HEAO-1 satellite, from August, 1977 until January 1979. The experiment consisted of six multi-layer, multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database table accesses the lightcurves available at HEASARC obtained from the A2 MED (small and large field of view) and HEDs (3 units, each with small and large field of view) detectors during the pointed phase. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/a2lcscan
- Title:
- HEAO 1 A2 Scanned Lightcurves
- Short Name:
- A2LCSCAN
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The A2 experiment was flown on the HEAO-1 satellite, from August, 1977 until January 1979. The experiment consisted of six multi-layer, multi-anode collimated gas proportional counters. These were two LEDs (Low Energy Detectors), a MED (Medium Energy Detector), and three HEDs (High Energy Detectors). The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started. This database table accesses the lightcurves available at HEASARC obtained from the A2 MED (small and large field of view) and HEDs (3 units, each with small and large field of view) detectors during the scanning phase. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/oso8alc
- Title:
- OSO8 A Detector Lightcurves
- Short Name:
- OSO8ALC
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database accesses the FITS lightcurves obtained from the A detector part of the GSFC Cosmic X-ray Spectroscopy experiment (GCXSE) on board OSO8. The Orbiting Solar Observatory-I (OSO-8) was launched on 21 June 1975 into a 550 km circular orbit at 33 degrees inclination. While the primary objectives of the mission were solar in nature, there were 3 detectors (the GCXSE detectors A, B and C) which had exclusively non-solar objectives. The energy band was 2-60 keV for the A and C detector and 2-20 keV for the B detector. The spacecraft structure consisted of a rotating cylindrical base section called the "wheel" and a non-spinning upper section called the "sail". The GCXSE detectors were mounted in the rotating wheel and their fields-of-view were either aligned to the spin axis (B and C) or at small angles to it (A), hence they always viewed the portion of the sky at right angles to the earth-sun line. The GCXSE detectors obtained data until late September 1978. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/oso8bclc
- Title:
- OSO8B&CDetectorLightcurves
- Short Name:
- OSO8BCLC
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- OSO8 B&C Detector Lightcurves This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/vela5b
- Title:
- Vela 5B All-Sky Monitor Lightcurves
- Short Name:
- VELA5B
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Data for these sources were obtained from the Vela 5B all-sky XC detector. The Vela 5B nuclear test detection satellite was part of a program run jointly by the Advanced Research Projects of the U.S. Department of Defense and the U.S.Atomic Energy Commission, managed by the U.S. Air Force. It was placed in a nearly circular orbit at a geocentric distance of ~118,000 km on 23 May 1969; the orbital period was ~112 hours. The satellite rotated about its spin axis with a ~64-sec period. The X-ray detector was located ~90 degrees from the spin axis, and so covered the celestial sphere twice per satellite orbit. Data were telemetered in 1-sec count accumulations. Vela 5B operated until 19 June 1979, although telemetry tracking was poor after mid-1976. The scintillation X-ray detector (XC) aboard Vela 5B consisted of two 1-mm-thick NaI(Tl) crystals mounted on photomultiplier tubes and covered by a 5-mil-thick beryllium window. Electronic thresholds provided two energy channels, 3-12 keV and 6-12 keV. In front of each crystal was a slat collimator providing a FWHM aperture of ~6.1x6.1 degrees. The effective detector area was ~26 sq-cm. Sensitivity to celestial sources was severely limited by the intrinsic detector background of ~36 cts/sec. The Vela 5B X-ray detector yielded ~40 cts/sec for the Crab, so 1 Vela ct/sec ~25 UFU~4.5E-10 ergs/sq-cm/sec in the 3-12 keV response band. This is a service provided by NASA HEASARC .
