m (→Options for spherical projection and deprojection:) |
m (→Examples:) |
||
Line 130: | Line 130: | ||
: The first step is to make a projection from the sky, centered around the center of our image: | : The first step is to make a projection from the sky, centered around the center of our image: | ||
− | |||
− | |||
:: grtrans '''--input''' catalog.dat '''--wcs''' tan,degrees,ra=220,dec=25 '''--col-radec''' 2,3 '''--col-out''' 5,6 '''--output''' img.proj | :: grtrans '''--input''' catalog.dat '''--wcs''' tan,degrees,ra=220,dec=25 '''--col-radec''' 2,3 '''--col-out''' 5,6 '''--output''' img.proj | ||
: The second step is the point matching: | : The second step is the point matching: | ||
− | |||
− | |||
:: grmatch '''--reference''' img.proj '''--col-ref''' 5,6 '''--col-ref-ordering''' '''-4''' '''--input''' img.star '''--col-inp''' 1,2 '''--col-inp-ordering''' +3 '''--match-points''' '''--order''' 4 '''--triangulation''' auto,unitarity=0.01,maxnumber=1000,conformable '''--max-distance''' 1 '''--weight''' reference,column=4,magnitude,power=2 '''--comment''' '''--output-transformation''' img.trans | :: grmatch '''--reference''' img.proj '''--col-ref''' 5,6 '''--col-ref-ordering''' '''-4''' '''--input''' img.star '''--col-inp''' 1,2 '''--col-inp-ordering''' +3 '''--match-points''' '''--order''' 4 '''--triangulation''' auto,unitarity=0.01,maxnumber=1000,conformable '''--max-distance''' 1 '''--weight''' reference,column=4,magnitude,power=2 '''--comment''' '''--output-transformation''' img.trans | ||
Line 145: | Line 141: | ||
: The next step is the astrometrical transformation, we create a "local" catalog, which is the original catalog extended with the proper X and Y plate coordinates: | : The next step is the astrometrical transformation, we create a "local" catalog, which is the original catalog extended with the proper X and Y plate coordinates: | ||
− | |||
− | |||
:: grtrans '''--input''' img.proj '''--col-xy''' 5,6 '''--input-transformation''' img.trans '''--col-out''' 7,8 '''--output''' img.cat | :: grtrans '''--input''' img.proj '''--col-xy''' 5,6 '''--input-transformation''' img.trans '''--col-out''' 7,8 '''--output''' img.cat | ||
: This invocation yields an other new file, "img.cat" which has 8 columns. The first six columns are the same as it was in "img.proj" (identifier, RA, DEC, magnitude and projected X, Y coordinates), the last two colums are the fitted plate coordinates. Then, the proper WCS headers can be determined by the following call: | : This invocation yields an other new file, "img.cat" which has 8 columns. The first six columns are the same as it was in "img.proj" (identifier, RA, DEC, magnitude and projected X, Y coordinates), the last two colums are the fitted plate coordinates. Then, the proper WCS headers can be determined by the following call: | ||
− | |||
− | |||
:: grtrans '''--input''' img.cat '''--col-ref''' 2,3 '''--col-fit''' 7,8 '''--wcs''' tan,order=4,ra=220,dec=25 >img.wcs | :: grtrans '''--input''' img.cat '''--col-ref''' 2,3 '''--col-fit''' 7,8 '''--wcs''' tan,order=4,ra=220,dec=25 >img.wcs | ||
: The newly created file, img.wcs contains the FITS "keyword"="value" pairs, which can be exported to "img.fits" to have a standard header extended by the WCS information. For exporting, the program fiheader(1) can be used: | : The newly created file, img.wcs contains the FITS "keyword"="value" pairs, which can be exported to "img.fits" to have a standard header extended by the WCS information. For exporting, the program fiheader(1) can be used: | ||
− | |||
− | |||
:: fiheader img.fits '''--rewrite''' '''--update''' $(cat img.wcs) | :: fiheader img.fits '''--rewrite''' '''--update''' $(cat img.wcs) | ||
: Note that the last two grtrans calls can be replaced by a single pipeline, when the file img.cat is not created: | : Note that the last two grtrans calls can be replaced by a single pipeline, when the file img.cat is not created: | ||
− | |||
− | |||
:: grtrans '''--input''' img.proj '''--col-xy''' 5,6 '''--input-transformation''' img.trans '''--col-out''' 7,8 '''--output''' '''-''' | grtrans '''--input''' '''-''' '''--col-ref''' 2,3 '''--col-fit''' 7,8 '''--wcs''' tan,order=4,ra=220,dec=25 >img.wcs | :: grtrans '''--input''' img.proj '''--col-xy''' 5,6 '''--input-transformation''' img.trans '''--col-out''' 7,8 '''--output''' '''-''' | grtrans '''--input''' '''-''' '''--col-ref''' 2,3 '''--col-fit''' 7,8 '''--wcs''' tan,order=4,ra=220,dec=25 >img.wcs |