AIPS HELP file for ALTDEF in 31DEC22
As of Sun Mar 26 8:57:00 2023
ALTDEF: Verb to modify velocity vs frequency relationship
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
AXTYPE 'OPT' or 'RAD' plus 'LSR',
'HEL', or 'OBS'
AXVAL Velocity at (new) ref. pixel=
AXVAL(1) + AXVAL(2).
AXREF Reference pixel location
RESTFREQ 0.0 1.E20 Rest frequency in HZ =
RESTFREQ(1) + RESTFREQ(2)
Use: ALTDEF is used to add or alter the description in the
catalogue map header of the relationship between the
spectral-line velocity and the frequency. The verb
ALTSWTCH is used to select which description is normally
used in labeling the image.
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.
AXTYPE......Two-part string choosing 'OPT'ical or 'RAD'io
definition of velocity and 'LSR', 'HEL'iocentric,
or 'OBS'erver velocity zero-point. The latter
choice only affects labeling. For example,
AXTYPE = 'RAD LSR' selects the LSR-relative
velocities in the radio convention. 'LSR'
and 'OPT' are the defaults.
AXVAL.......Velocity at (new) reference pixel. Value is
AXVAL(1) + AXVAL(2) in double precision. No
default. Units are meters/sec.
AXREF.......Reference pixel location for velocities. No
RESTFREQ....Line rest frequency in Hz = RESTFREQ(1) +
RESTFREQ(2) in double precision.