European Helio- and Asteroseismology Network (HELAS)
Local Helioseismology Network Activity
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Example FITS file MDI headerA fairly self explanatory header. Some additional notes on the parameters are shown below.---------------------------------------------------------------
SIMPLE = T / Fits standard
BITPIX = 16 / Bits per pixel
NAXIS = 3 / Number of axes
NAXIS1 = 512 / Axis length
NAXIS2 = 512 / Axis length
NAXIS3 = 1440 / Axis length
EXTEND = F / File may contain extensions
IRAF-TLM= '14:03:03 (01/08/2006)' / Time of last modification
BSCALE = 1.000000000000E+00
BZERO = 0.000000000000E+00
BLANK = -32768
HISTORY created by fastrack V 1.7 Tue Aug 1 13:43:29 2006
ORIGIN = 'SOI Science Support Center' / SOI SDS V 4.5
AUTHOR = 'Tom Duvall'
DATE = '2006-08-01' / file creation date
T_START = '2002.01.23_23:59:28.0_UT' / nominal
T_STOP = '2002.01.24_23:58:28.0_UT' / nominal
T_STEP = '1minute'
T_REC = '2002.01.24_11:58:58.0_UT' / midpoint of nominal interval
T_FIRST = '2002.01.24_00:00:28.0_UT' / for first actual image (before masking)
T_LAST = '2002.01.24_23:58:28.0_UT' / for last actual image (before masking)
T_OBS = '2002.01.24_11:59:28.0_UT' / midpoint of first and last images
MIN_CONE= 0.000000000000E+00 / radius of tracked region (degree)
MAPSCALE= 1.200000000000E-01 / degree / pixel
MAP_PROJ= 'Postels '
TRACKOPT= 'Eulerian'
MERID_V = 0.000000000000E+00 / microradian / sec
TRACK_A0= -1.500000000000E-02 / microradian / sec
TRACK_A2= -3.390000000000E-01 / sin**2(lat) term
TRACK_A4= -4.850000000000E-01 / sin**4(lat) term
BACKGRND= '/scr39/duvall/AR9787/TrkV_020124/bkgd.fits' / average image subtracte
HG_LAT = -8.300000000000E+00 / degree (at map center)
HG_LONG = 1.328000000000E+02 / degree (at map center)
TSAM = 60.
MEANBACK= -262.6583
FIXED = 0
END
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Description
SIMPLE Mandatory. File type. Mandatory in primary header. Must
be F(alse) if the file does not conform to the FITS
standard, otherwise T(rue). Must be first keyword in
header.
BITPIX Mandatory FITS data type. Must be second keyword
in header.
BSCALE Scaling factor to convert data to float. FITS only.
BZERO Offset applied to true pixel values. FITS only.
physical_value = fits_pixel_value*bscale + bzero
NAXIS Mandatory. Number of axes. Must be third keyword in header.
NAXIS1 Mandatory. Size of first dimension. Must follow NAXIS
in header.
NAXIS2 Mandatory. Size of second dimension. Must follow NAXIS1
in header.
T_FIRST UT start time of observation (center of averaging
interval).
T_LAST UT end time of observation (center of averaging
interval).
T_OBS Actual (center) of integration time.
T_REC Intended observation time.
T_START Beginning time of first image in a data set.
T_STOP Just past ending time of last image in a data set.
MAPSCALE Scale of maps in heliographic degrees / pixel at an
appropriate location.
MAP_PROJ Type of projection used.
TRACKOPT Type of tracking used.
MERID_V
TRACK_A0 a0, a2, and a4 are the coefficients in a
TRACK_A2 sin^2 (latitude) expansion of the dif-
TRACK_A4 ferential rotation rate, minus the Car-
rington rotation, in microradian / sec.
Thus, if they are all 0, rigid
Carrington rotation is assumed.
BACKGRND A background image subtracted from the dataset.
HG_LAT The heliographic latitude of map centre. The zero
latitude is defined as the solar equator, increasing
to +90 degrees towards the North and decreasing to
-90 degrees towards the South.
HG_LONG The heliographic longitude of map centre.The zero
longitude is defined as the longitude that passed
through the ascending node of the solar equator on
the ecliptic plane on 1 January, 1854 at 12 UT
(Julian day = 2398220.0). The longitudes are also
known as Carrington longitudes.
TSAM ???
MEANBACK Mean value of the background image.
FIXED ???
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