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Introduction
Summary of LASCO/EIT What is LASCO? What is EIT? (external link) FAQ Realtime Images RealTime Movies (SOHO Movie Theater) Download LASCO Data Data Products Image Gallery Movie Gallery Processing Levels FITS Header Keywords Data Policy Wavelet images/movies Coronal Mass Ejections Eclipse Observations LASCO Calibration LASCO C3 Planet transits (via Sungrazer) Team and Operations Resources LASCO/C1 at MPAe (Germany) LASCO at LAS (France) LASCO Handbook Technical Notes Detailed Documentation Acronyms Solwind Images and CMEs SOHO Home page SOHO and SOHO Instruments Other Solar Satellites and Observatories |
DEFINITION OF FITS HEADER KEYWORDSNOTE: 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
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