IPCUNSCRND - Einstein IPC Unscreened Photon Event List
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.
Each entry in this database has associated with it 4 data files in FITS format and one in ascii. The FITS files are : the unscreened photons list ('up'), the source detection file ('sd'), the barycenter timing file ('bt') and the background file ('bk'). The ascii file ('ls') contains a summary of the observation.
The 'up' file contains seven extensions, including an observation log, good time intervals, and an event table. The 'sd' contains a minimum of four extensions, which store the information about the detected sources, and in addition there are two extensions for each detected source containing the spectrum. The 'bt' file has three extensions, which include the solar system barycenter time correction and ephemeris.
This database table uses the information stored in the keywords of the EVENT extension FITS file ('up'). The following keywords were utilized: DATE_OBS TIME-OBS, DATE_END TIME-END, NAXIS2, RA_NOM DEC_NOM, OBJECT, OBJCLASS, OBS_ID, TITLE, ONTIME.
Name of target as given in the OBJECT keyword of the event FITS extension.
Observation start time.
Observation stop time
Number of rows in the event extension. This corresponds to the number of photons detected in the observation.
The Right Ascension of the nominal pointing in the selected equinox. The Right Ascension and the Declination are the content of the keywords RA_NOM and DEC_NOM in the Event extension. They give the nominal pointing direction of the spacecraft during the observation.
The Declination of the nominal pointing in the selected equinox. The Right Ascension and the Declination are the content of the keywords RA_NOM and DEC_NOM in the Event extension. They give the nominal pointing direction of the spacecraft during the observation.
The Galactic Longitude of the nominal pointing direction of the spacecraft during the observation.
The Galactic Latitude of the nominal pointing direction of the spacecraft during the observation.
Broad classification of the object type. This is divided into the following 13 categories, and they are : AGN, Cluster of galaxy, Galaxy, Gamma Ray Source, Nebula, Solar System Object, Star, Star Cluster, Supernova Remnant, X-ray Source, Survey Field, ?, and no observation.
This parameter contains the Einstein sequence number associated with the observation.
The observation title as given in the TITLE keyword.
This parameter contains the exposure time in seconds.
The HEASARC class parameter as derived from the value in the Obj_Class parameter. There was not always a unique match to the HEASARC classes.
The HEASARC classes in the following cases were set according to the following:
Unknown for Obj_Class ? and No Observation Star Unclassified for Obj_Class Star and Star cluster X-ray Binary for Obj_Class X-Ray Source Diffuse X-ray emission for Obj_Class Survey Field
Name of the FITS file containing the event list extension.