The IPCPHOT database contains information from the Imaging Proportional Counter aboard HEAO-2, the Einstein Observatory, in Event List Format. Einstein incorporated a high-resolution X-ray telescope and a focal plane assembly capable of positioning at its focus one of four instruments: a high-resolution imaging detector (HRI), a broader-field imaging proportional counter (IPC), a solid state spectrometer (SSS), and a Bragg crystal spectrometer (FPCS). Einstein (HEAO-2) was launched on November 13, 1978, and operated successfully until April 1981. This is a service provided by NASA HEASARC .

The HRIIMAGE database table contains information from the High Resolution Imager aboard HEAO 2, the Einstein Observatory. Einstein incorporated a high-resolution X-ray telescope and a focal plane assembly capable of positioning at its focus one of four instruments: a high-resolution imaging detector (HRI), a broader-field imaging proportional counter (HRI), a solid state spectrometer (SSS), and a Bragg crystal spectrometer (FPCS). Einstein (HEAO 2) was launched on November 13, 1978, and operated successfully until April 1981. One duplicate entry was removed from the HEASARC implementation of this catalog in June 2019. This is a service provided by NASA HEASARC .

The HRIPHOT database contains information from the High Resolution Imager aboard HEAO-2, the Einstein Observatory, in Event List Format. Einstein incorporated a high-resolution X-ray telescope and a focal plane assembly capable of positioning at its focus one of four instruments: a high- resolution imaging detector (HRI), a broader-field imaging proportional counter (IPC), a solid state spectrometer (SSS), and a Bragg crystal spectrometer (FPCS). Einstein (HEAO-2) was launched on November 13, 1978, and operated successfully until April 1981. This is a service provided by NASA HEASARC .

This database table gives access to the IPC unscreened data set, which includes files in the event list format together with auxiliary files. This data set was generated by the Einstein Data Center and delivered to the HEASARC on CD-ROM. The Einstein Observatory (HEAO-2) operated from November 1978 to April 1981. Einstein carried the first fully imaging X-ray telescope in space and operated in pointing mode. The Imaging Proportional Counter had a bandpass of 0.2-3.5 keV and was one of two detectors onboard used for imaging. During the Einstein lifetime more than 4000 targets were observed with the IPC. This database table was last updated by the HEASARC in August 2005. Galactic coordinates were added and some parameters were renamed to adhere to the HEASARC's current parameter naming conventions. This is a service provided by NASA HEASARC .

This database contains information on sources detected with the Einstein Observatory Image Proportional Counter (IPC), assembled for the Einstein Observatory Catalog (EOSCAT) of IPC X-ray Sources (2E) and containing over 4000 unique sources (with 6539 separate detections) which were detected with the IPC at a level of significance greater than 3.5 sigma in the broad band (0.2-3.5 keV). This database also contains the list of 277 sources which are known not to have been included in the Einstein Observatory Source Catalog (flagged by supplement = 'Y' in this database). Those which were not detected during the standard Rev1B processing were typically discovered upon visual inspection of the contour diagrams in the Catalog. Others were detected with Rev1B standard processing but left out of the Catalog because of short exposure times or other reasons listed in the "missed_code" field. 258 of these 277 additional sources have no valid signal to noise ratio (SNR) estimate (values of 0.0), while 3 others have SNR values of 3.2 and 3.3, notice. This IPC database is based on NASA Astrophysics Data System (ADS) tables that were created in 1991 and 1993 and were themselves derived from tables provided by Dr. D. E. Harris of the Center for Astrophysics at Harvard-Smithsonian. The HEASARC has a similar catalog in its database called EINSTEIN2E which comprises a more recent version of the IPC source list as archived at the NASA Astronomical Data Center (ADC) and the Center for Astronomical Data at Strasbourg (CDS). EINSTEIN2E has 868 fewer detections than the IPC catalog, notice, for reasons that the HEASARC is unsure of, but that may imply that some of the detections in IPC are not reliable. We have retained the IPC database for reasons of completeness, but caution that detections listed here which have no counterpart in the EINSTEIN2E Catalog should be treated with caution. This IPC database was recreated by the HEASARC in December 2000 to replace a previous version in which we discovered some transcription errors. It is based on NASA Astrophysics Data System (ADS) tables that were created in 1991 and 1993 and were themselves derived from tables provided by Dr. D. E. Harris of the Center for Astrophysics at Harvard-Smithsonian:

 The Einstein IPC Source List From EOSCAT (ADS Creation Date: 26-Dec-1990; ADS Last Revision Date: 04-Nov-1993), D.E. Harris, CfA The EOSCAT List of Missed IPC Sources (ADS Creation Date: 26-Oct-1990; ADS Last Revision Date: 17-Sep-1991), D.E. Harris, CfA 

This is a service provided by NASA HEASARC .

The Einstein Observatory (also known as HEAO-2 or HEAO-B) was operational from 1978 November 13 until 1981 April 25 when the Einstein attitude control system failed. The Monitor Proportional Counter (MPC) was a non-focal plane instrument that monitored the 1 to 20 keV X-ray flux of the source(s) being observed simultaneously by the operational focal plane instrument. The MPC was a collimated proportional counter filled with argon and carbon dioxide. It had a circular field of view, 1.5 degrees in diameter (FWHM), which was co-aligned with the telescope. A 1.5 mil Be window sealed the gas in the detector and shielded the detector from ultraviolet radiation. The active area of the MPC was 667 square cm. The MPC obtained useful data from 1978 November 19 until 1981 April 17, with the exception of a 3-month period from 1980 Aug 27 to 1980 Dec 08 when operation was intermittent, due to Einstein Observatory attitude control problems. The characteristics of the MPC have been described in detail by Gaillardetz et al.(1979) and by Grindlay et al. (1980). One duplicate entry was removed from the HEASARC implementation of this catalog in June 2019. This is a service provided by NASA HEASARC .

IPCDEEP is created from a table containing basic source parameters for each of the 178 IPC sources detected by the Einstein Deep Survey. The Einstein Deep Survey program (EDS) consists of very deep X-ray exposures in selected regions of the sky at high galactic latitude. The main purposes of the survey are to investigate the nature of the extragalactic X-ray background through direct source counts at very low flux levels and to study the nature of the very faint X-ray sources which comprise a significant fraction, if not all, of the soft X-ray background. This is a service provided by NASA HEASARC .

The X-ray sources from observations made with the Einstein Observatory (HEAO-2) Imaging Proportional Counter (IPC) that have intensities of 2-sigma or more above the background are compiled in this catalog. This catalog covers more sky at fainter flux levels than the Einstein Medium Sensitivity Survey. Fields with diffuse emission sources such as bright Abell clusters of galaxies and supernova remnants were excluded. Thus, data within 10 degrees of the galactic plane as well as fields within the boundaries of the Magellanic Clouds were excluded. Regions crowded with galactic sources such as the Orion and Pleiades fiels were also excluded. Excluding redundant fields, this catalog covers 1850 sq. degrees of the sky. The generation of the Einstein Two-Sigma Catalog was described in detail by Moran et al. (1996). Please read this article carefully to ensure responsible use of the Catalog. Detailed scientific and technical questions on the contents and methodology of this catalog should be addressed to the first author, Ed Moran (edhed@igpp.llnl.gov). In particular, it should be noted that, by design, this catalog contains a significant number of spurious sources: only 28%, or about 13,000 sources, out of the 46,000 source in the 2-sigma catalog are `real` astrophysical sources, with the remainder of the sources being spurious ones. Moran et al. show in their paper that performing cross-correlations of 2-sigma sources with other catalogs is an effective way of selecting sources in this catalog that are probably real. This is a service provided by NASA HEASARC .

The Heliospheric Imager-1 (HI-1) telescope is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU. The HI-1 telescope observes the inner heliosphere from 12 to 84 solar radii with the band-pass wavelength of 450-750 nm.