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: http://hea-www.harvard.edu/PROS/PUG/node207.html
Дата изменения: Unknown Дата индексирования: Mon Oct 1 23:31:35 2012 Кодировка: Поисковые слова: meteor shower |
Although the spatial variation of the quantum efficiency
across the HRI is nominally within 10% for most of the detector,
occasionally it may be desirable to flat-field a map with preflight
calibration measurements.
cl> imhead rh*.qp | match ROLL_NOM
NOTE: The roll angle for US processed REV 0 data is given with different signs in the header compared to that of the printout (which is correct). Therefore the above method should be used only for RDF data.
> ftp sao-ftp.harvard.edu > cd /pub/rosat/calfiles > ascii > get README > binary > get roshri_qe8.fits > quit
> images > rotate
NOTE: use the following parameters
rotation angle= | (switch the sign of the ROLL_NOM) |
xin=252.5 | |
yin=252.5 | |
xout=INDEF | |
yout=INDEF | |
ncols=512 | |
nlines=512 | |
interpo=poly3 | |
boundary=constant | |
constant=0.0 |
> display rh*_im1.imh
In Iraf: >images >listpix "rh*.imh[4050:4070,4070:4090] wcs=physical" -where the coordinates are the image section of interest.
N.B. The source intensity correction given in the SASS output is the QEC factor.
The wobble means that a general area of the detector/QE map will contribute to any give source; hence the above method is approximate.