eq2coe -- convert a sky position (RA, Dec) to a pixel position on a
coadded (COE) image tile
eq2coe ra dec
- ra = 0.0 [real]
- The right ascension in degrees
- dec = 0.0 [real]
- The declination in degrees
- (raref = 0.0) [real]
- The right ascension in degrees of the centre of the super-image to which the supplied sky position is to be transformed.
- (decref = 0.0) [real]
- The declination in degrees of the centre of the super-image to which the supplied sky position is to be transformed.
- (outscl = 0.27) [real]
- The scale in arcseconds per pixel of the super-image to which the supplied sky position is to be transformed.
- (secnx = 4096)
- The size of the sections of the superimage in X. It is assumed that the superimage is in sections with the reference position at the centre of the central section. If the specified point is beyond the central section the pixel position, and relative offsets of the appropriate section are given.
- (secny = 4096)
- The size of the sections of the superimage in Y. It is assumed that the superimage is in sections with the reference position at the centre of the central section. If the specified point is beyond the central section the pixel position, and relative offsets of the appropriate section are given.
eq2coe converts a equatorial sky position (RA,Dec) in degrees to a pixel position on a tile of a superimage in COE (conic equal-area projection). If the specified position is the same as the reference position then the result will be the middle of the central section (tile).
If the position is further from the centre it may fall on a different section (tile) and in this case the result is the pixel position on that section:ei> eq2coe 0 30 raref=0 decref=30 outscl=0.2 RA (deg) Dec (deg) Section X (pix) Y 0.000000 30.000000 0 0 2048.00 2048.00
ei> eq2coe 0.3 30.6 raref=0 decref=30 outscl=0.2 RA (deg) Dec (deg) Section X (pix) Y 0.300000 30.600000 -1 3 1495.74 565.89
It takes practically no time at all.
drizzle,parapredriz,coe2eq,stsdas.toolbox.imgtools.rd2eq