AIPS HELP file for CELGAL in 31DEC21
As of Tue Oct 26 21:26:17 2021
CELGAL: Verb to switch between Celestial and Galactic coords
INNAME Image name(name).
INCLASS Image name(class).
INSEQ 0.0 9999.0 Image name(seq. #). 0=>high
INDISK 0.0 9.0 Disk drive #. 0=>any
Use: CELGAL switches the axis descriptions between Celestial
and Galactic coordinates. The verb works for images
projected simply to the tangent plane. These projections
are indicated in the image header by the strings '-SIN',
'-TAN', and '-ARC' which describe the kind of projection
(VLA, standard optical, and Schmidt or equal-angle,
INNAME......Image name(name). Standard defaults.
INCLASS.....Image name(class). Standard defaults.
INSEQ.......Image name(seq. #). 0 => highest.
INDISK......Disk drive # of image. 0 => any.
CELGAL: Verb to transform the coordinate system between Ra and
Dec and the Galactic coordinate system.
The coordinate transformation is implimented as a simple
rotation between the two coordinate systems as a function of
three parameters. The three parameters are the coordinate of
the north galactic pole in (1) RA and (2) Dec and (3) galactic
latitude of the North celestial pole. These three parameters
are a function of the epoch of observation (ie B1950 or J2000).
If the epoch of observation is not 1950, the coordinate
transformation for J2000 is used.
For coordinate parameters are tabulated below:
N. Galactic Pole N. Celestial Pole
Epoch Ra Dec latitude
(degrees) (degrees) (degrees)
1950 192.25 24.4 123.0
2000 182.859375 27.128653 123.932018