IPCIMAGE - Einstein IPC Images
FITS keyword: BSCALE
Array elements are converted to integers, scaled to +/- 32767. This is done by finding the maximum and minimum (datamax and datamin) and using the equation:
FITS keyword: BZERO
`BZERO` is the offset to the true pixel values.
The true pixel value is found using the scaled value TAPE in the following equations:
TAPE = (TRUE - BZERO)/BSCALE TRUE = (TAPE*BSCALE) + BZERO
FITS keyword: CRVAL1
The RA reference point value of the FITS image file. The right ascension (1950.0) in decimal degrees of the center of the image.
FITS keyword: CRVAL2
The DEC reference point value of the FITS image file. The declination (1950.0) in decimal degrees of the center of the image.
FITS keyword: CRPIX1
Pixel coordinates of `RA` in image center of the FITS image file. The RA reference pixel location.
FITS keyword: CRPIX2
Pixel coordinates of `DEC` in image center of the FITS image file. The declination reference pixel location.
FITS keyword: CDELT1
The RA increment along axis of the FITS image file.
FITS keyword: CDELT2
The DEC increment along axis of the FITS image file.
FITS keyword: CROTA1
FITS keyword: CROTA2
FITS keyword: DATAMAX
True peak intensity within the FITS image file.
FITS keyword: DATAMIN
True minimum intensity within the FITS image file.
FITS keyword: TSIGMA
Three sigma level at field center within the FITS image file.
FITS keyword: DSBKG
Total number of Deep Survey (DS) counts in background map within the FITS image file.
FITS keyword: BEBKG
Total number of Bright Earth (BE) counts in background map within the FITS image file.
FITS keyword: ROLL_ANG
The angle in degrees which measures the roll of the spacecraft about an axis pointing toward the field center. A positive value indicates a clockwise rotation of the detector's FOV.
FITS keyword: BAD_ASP
Bad Aspect: 0 if observation is characterized by average roll angle, 1 otherwise. If 1, do not use roll angle.
FITS keyword: TIME_LIV
A measure of the effective exposure time for the field center. TIME_LIV is the total number of seconds during which the detectors were able to gather data, corrected for Earth occultation, SAA, bad aspect solution and detector dead time.
FITS keyword: OBJECT
Object sequence number in the Einstein catalog.
FITS keyword: AVGOFFY
Average translation offsets (in 8 arcsec pixels) from nominal pointing direction on y axis.
FITS keyword: AVGOFFZ
Average translation offsets (in 8 arcsec pixels) from nominal pointing direction on z axis.
FITS keyword: RMSOFFY
Root mean square of instantaneous pointing offsets from average defined by `Y OFFSET AVG`. This is useful in assessing stability of pointing.
FITS keyword: RMSOFFZ
Root mean square of instantaneous pointing offsets from average defined by `Z OFFSET AVG`. This is useful in assessing stability of pointing.
FITS keyword: INSTRUME
Focal plane detector, always `IPC` in this catalog.
FITS keyword: OBSERVER
Party responsible for collecting this particular observation, where 0 = CFA, 1 = CAL, 2 = MIT, 3 = GSFC.
FITS keyword: GALL
Galactic Longitude of field center of the FITS image file.
FITS keyword: GALB
Galactic Latitude of field center of the FITS image file.
FITS keyword: DATE_OBS
Observation start time.
FITS keyword: DATE_STP
Observation stop time.
FITS keyword: NH
Column density of neutral hydrogen in atoms/cm**2 integrated along the line of sight through our galaxy in the direction of the target.
FITS keyword: TITLE
Information on the nature of the target. Entries include catalog names (e.g., 4U0248-85) and observer's notes.
FITS keyword: DATE
FITS image file creation date.
File name of the FITS image file in the BROWSE database. These files are of the form `*hhmmDdd.*`. The leading * can be either `I` or `M`, `I` denoting "IPC" and `M` denoting "Merged". The letters `hhmm` denote the RA hour and minute. The `D` is either `N` or `S` for North or South and `dd` is the Declination in degrees. The trailing * can be `XI` for "X-ray Intensity" or `RE` for "Relative Exposure". Final letters such as A, B, C distinguish XI and RE files when the rest of the file name is not unique.
File name of the GIF file created from the FITS image file. The file names follow the format `**hhmmDdd.gif`. The leading * is a letter such A, B, C, etc., to distinguish the files when the rest of the file name is not unique. The second * is either `I` or `M`, I denoting "IPC" and `M` denoting "Merged". The letters `hhmm` denote the RA hour and minute. The `D` is either `N` or `S` for North or South, and `dd` is the Declination in degrees.