[daip] aips_gripe

[Lincoln Greenhill]

Dear Leonia,

I am concerned about the formula at the bottom of page 2 of the 
AIPS memo you refer to (#27).

For small velocities, for identical reference pixels in velocity
and frequency, and
for the radio definition of 
redshift, this formula does not approach the limit I expect

delta-velocity = speed-of-light * delta-nu / REST-FREQUENCY 

Why is that?

Regards,

lincoln


BTW - I may have been responsible for dropping the discussion of an update
to CVEL so that it would spare the user an unnecessary calculation of
velocity.  If this is true, let me know whatever questions I may have
failed to answer.


Lincoln J. Greenhill      Harvard-Smithsonian Center for Astrophysics 
Radio & Geoastronomy Division, 60 Garden St, Cambridge, MA 02138, USA
Telephone:  1 617-495-7194             FAX:  1 617-495-7345
Internet:  greenhill at cfa.harvard.edu   http://cfa-www.harvard.edu/~lincoln