### Radio-projected cubes

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.