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: http://xmm.vilspa.esa.es/sas/7.0.0/doc/omatt/node8.html
Дата изменения: Thu Jun 29 00:53:08 2006 Дата индексирования: Sat Dec 22 07:26:41 2007 Кодировка: Поисковые слова: arp 220 |
subroutine omatt
open output file
read the OSW window parameters, binning factors from header
call CAL_GetBoresightMat
call OAL_GetAttitude (with time of reference frame)
find OM boresight direction
rotate by roll angle
loop over individual source information
read in individual source information
extract pixel position
correct for distortion (CAL_omDistortion)
call to CAL_omPlatescale to get linear plate-scale
perform co-ordinate conversion
(including s/c boresight offset correction and roll angle)
end loop
Add columns for the RA and dec of each source to the source-list file.
if (usecat) then
read in the catalogue data.
Set up a grid of offsets deltax and deltay in the x and y directions.
Sort these offsets into increasing radius order from the origin.
For each grid shift the stars by deltax and deltay in the x
and y directions.
Try to match each star with one in the catalogue by computing the
distance between it and the selected catalogue stars and regarding
it as matched if the distance is less than the specified tolerance.
For each pair of offsets compute a maximum-likelihood parameter and take
the pair with the maximum value as the best offsets.
Use these offsets to repeat the star matching, and then perform a
least-squres fit to improve the offsets and also determine any small
rotation between the two coordinate systems.
Determine errors on the computed parameters by a Monte Carlo procedure
which generates artificial data sets from the original, computes the
parameters for each simulation, and then at the end computes the mean and
standard deviations of all the parameters.
Correct the RAs and Dec of the sources using the computed paramters.
Added corrected RA and Dec columns to the source-list file, and also
information about the fit.
end if
Rebin, rotate and correct for distortion the image, and write out to a fits file.
close OSWSL
close output file
end subroutine omatt