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The cubes using a radio-projection in GILDAS typically look like:
File : 13co10.lmv REAL*4
Size Reference Pixel Value Increment
61 44.5561196503335 0.00000000000000 -5.411193342297338E-05
101 55.4797321532119 0.00000000000000 5.411193342297338E-05
921 578.812988281250 2.50000000000000 -0.106259830296040
Source name NGC7023
Axis type RA DEC VELOCITY
Coordinate system EQUATORIAL Velocity LSR
Right Ascension 21:01:32.24000 Declination 68:10:29.5500
Equinox 2000.0000
Projection type RADIO Angle 0.000000000000000
Axis 1 A0 21:01:32.24000 Axis 2 D0 68:10:29.5500
[...]
Note the RADIO projection type. Starting from GILDAS version aug23, this kind of header will be implicitely
exported with the SFL projection by the V
FITS
command. The resulting header will be:
NAXIS = 3 / NAXIS1 = 61 / NAXIS2 = 101 / NAXIS3 = 921 / CTYPE1 = 'RA---SFL ' / CRVAL1 = 0.3153843333333E+03 / CDELT1 = -0.3100385406429E-02 / CRPIX1 = 0.4455611965033E+02 / CUNIT1 = 'deg ' / CTYPE2 = 'DEC--SFL ' / CRVAL2 = 0.0000000000000E+00 / CDELT2 = 0.3100385406429E-02 / CRPIX2 = -0.2193368163425E+05 / CUNIT2 = 'deg ' / OBJECT = 'NGC7023 ' / RADESYS = 'FK5' / Coordinate system RA = 0.3153843333333E+03 / Right Ascension DEC = 0.6817487500002E+02 / Declination [...]Note 1) the -SFL suffix on the spatial axes, 2) the null CRVAL2 value, 3) the reference pixel shifted far away, to the Equator (CRPIX2 is about
pixels). Note also that the
indicative source position (RA,DEC) is preserved.