Summary of LASCO/EIT
What is LASCO?
What is EIT? (external link)
RealTime Movies (SOHO Movie Theater)
Database Queries and Download
CME Queries (New!)
FITS Header Keywords
Coronal Mass Ejections
LASCO Sky Map
LASCO C3 Planet transits (via Sungrazer)
Latest Site Updates
Team and Operations
LASCO/C1 at MPAe (Germany)
LASCO at LAS (France)
Solwind Images and CMEs
SOHO Home page
SOHO and SOHO Instruments
Other Solar Satellites and Observatories
DEFINITION OF FITS HEADER KEYWORDS
NOTE: LASCO Level-1 FITS keywords are described in this pdf document.
The following table has 4 columns, KEYWORD, TYPE, VALUES, and DESCRIPTION.
KEYWORD gives the name of the FITS keyword and may be up to 8 characters.
TYPE refers to the data type and the size of the data:
S String I Integer R RealThe size of the data depends upon the data type. For example S*2 is a 2 character string, whereas I*2 is a 2 byte integer (16 bits).
VALUES shows the range of values that the KEYWORD can take.
DESCRIPTION gives a short description of the keyword.
KEYWORD TYPE VALUES DESCRIPTION SIMPLE S*1 T Conforms to FITS standard BITPIX I*2 8,16,32 Number of bits per pixel NAXIS I*2 2 Number of axes in the image NAXIS1 I*2 Positive Length of the first axis (columns) Number NAXIS2 I*2 Positive Length of the second axis (rows) Number TELESCOP S*8 SOHO Name of the satellite INSTRUME S*8 LASCO Name of the instrument DETECTOR S*8 C1,C2,C3 Name of the telescope within LASCO FILENAME S*30 Any Name of the FITS file. For the archive data we conform to the DOS 8.3 standard. FILEORIG S*17 Any Name of the raw telemetry file in the format YYMMDD_HHMMSS.img. The implied date and time are the date and time stamp of when the data were put into the telemetry stream. DATE S*23 Any Date of file generation in CSSDS standard format, eg 1996/05/21 17:28:48.208 DATE-OBS S*10 Any Date of the start of the exposure, eg: 1996/05/20 TIME-OBS S*12 Any Time of the start of the exposure, eg: 00:40:05.407 MID_DATE I*2 Any Modified Julian Date at the mid- point of the exposure MID_TIME R*4 Any Number of seconds of the day at the mid-point of the exposure OBT_TIME R*4 Any Value of the On-Board Time EXPTIME R*4 Any Number of seconds of the exposure time EXP0 R*4 Any Measured exposure delay time EXPCMD R*4 Any Commanded exposure delay time EXP1 R*4 Any Length of time since CCD clear EXP2 R*4 Any Length of time to open shutter EXP3 R*4 Any Length of time to close shutter READPORT S*1 A,B,C,D CCD readout port SUMROW I*2 0,2,4 Number of rows being summed on the CCD SUMCOL I*2 0,2,4 Number of columns being summed on the CCD LEBXSUM I*2 1,2,4,.. Number of columns being summed in the LEB LEBYSUM I*2 1,2,4,.. Number of rows being summed in the LEB SHUTTR I*2 0 Shutter was commanded open during the exposure 1 Shutter was not commanded during the exposure LAMP I*2 0 Calibration lamp was not commanded on 1 Calibration lamp was commanded on FILTER S*8 Clear Position of the filter wheel Orange FeXIV FeX CaXV Blue Red IR Lens POLAR S*8 Clear Position of the polarizer wheel 0 deg +60 deg -60 deg H alpha ND LP_NUM S*8 Normal Description of the LEB Program (LP) used to Cal Lamp generate the image Dark Line Scan Pol Seq OS_NUM I*2 Any Observing Sequence Number An arbitrary number that specifies similar instrument configuration and can be used to search the data base for other exposures taken under the same conditions. IMGCTR I*2 Any Sequential counter since the last LEB reboot IMGSEQ I*2 Any Number of the image in the current sequence, starting at 0 COMPRSSN S*8 Code indicating the steps used in compressing the data PLATESCL R*4 Any Number of arc seconds per pixel OFFSET I*2 Any Electronic offset in DN P1COL I*2 Any CCD column number of start of image, 0-19 are underscan pixels, 20-1043 are imaging pixels, 1044 - 32000 are overscan pixels P1ROW I*2 Any CCD row number of start of image, 1-1044 are imaging rows, 1025-32000 are overscan rows P2COL I*2 Any CCD column number at end of image, 0-19 are underscan pixels, 20-1043 are imaging pixels, 1044 - 32000 are overscan pixels P2ROW I*2 Any CCD row number at end of image, 1-1044 are imaging rows, 1025-32000 are overscan rows RECTIFY S*8 TRUE Status of rectification to put solar north FALSE to the top of the image R1COL I*2 Any The rectified coordinate, equivalent to P1COL, as though the image had been read out with this coordinate R1ROW I*2 Any Rectified P1ROW R2COL I*2 Any Rectified P2COL R2ROW I*2 Any Rectified P2ROW EFFPORT S*8 A,B,C,D Rectified read out port VERSION I*2 Any Version number of LEB header DATAMIN R*4 Any Minimum value of the image, including the bias DATAMAX R*4 Any Maximum value of the image DATAZER I*4 Any Number of zero pixels in the image DATASAT I*4 Any Number of saturated values in the image DATAAVG R*4 Any Average value of the image DATASIG R*4 Any Standard deviation in computing the average DATAP01 I*4 Any Intensity of 1st percentile of image DATAP10 I*4 Any Intensity of 10th percentile image DATAP25 I*4 Any Intensity of 25th percentile of image DATAP75 I*4 Any Intensity of 75th percentile of image DATAP90 I*4 Any Intensity of 90th percentile of image DATAP95 I*4 Any Intensity of 95th percentile of image DATAP98 I*4 Any Intensity of 98th percentile of image DATAP99 I*4 Any Intensity of 99th percentile of image CRPIX1 R*4 Any Column number of the reference pixel. SOHO practice has been to use this as the center of the sun. CRPIX2 R*4 Any Row number of the reference pixel. SOHO practice has been to use this as the center of the sun. CRVAL1 R*4 Any Number of arc seconds of the center of the sun from the reference position in the azimuthal direction (E-W). Positive is to the solar west CRVAL2 R*4 Any Number of arc seconds of the center of the sun from the reference position in the elevation direction (N-S). Positive is to solar north CROTA1 R*4 Any Rotation of axis 1 with respect to solar north Positive is westward (clockwise) CROTA2 R*4 Any Rotation of axis 2 with respect to solar north Positive is westward (clockwise) CTYPE1 S*8 SOLAR-X Type of units of axis #1 CTYPE2 S*8 SOLAR-Y Type of units of axis #2 CUNIT1 S*8 ARCSEC Units along axis #1 CUNIT2 S*8 ARCSEC Units along axis #1 CDELT1 R*8 Any Increment along axis #1 (Same as PLATESCL) CDELT2 R*8 Any Increment along axis #1 (Same as PLATESCL) HISTORY S*80 Any History of processing. Can be repeated COMMENT S*80 Any Comments. Can be repeated END Last keyword in the FITS header