[AZ-Observing] Re: IC 1296

     The total magnitude of IC 1296 is not well in hand.  The photo-blue
value of 14.8 evidently quoted by Megastar is the Zwicky 'mz' magnitude
corrected for global systematic errors.  Don't know how anyone gets
15.1 from published data in the visible, though Jack doesn't specify
what passband it is supposed to be for.  The NED database, where one
shuld always look first for source data on galaxies, shows 2MASS
near-infrared photometry including total J magnitude of 13.0.  
The J passband is out at 1.2 microns.  Folks on the 'amastro' list
found that an empirical offset of "about 2" is in the ballpark for
the V-J color of typical galaxies.  Thus one could estimate V=15.0
(maybe +/- 0.5) for IC 1296.  Given the likely reddening in this part
of the sky together with the usual B-V color of a late-type galaxy
like this one, the B magnitude is something like 16.0.  Thus the
corrected blue magnitude of 14.8 is too bright (implies V of ~13.8),
but figures around 15th for visual are about right.  The standard
dimensions also imply mean surface brightness around 15.0, so this
is not an easy object.  I've seen it in a 16-inch from Anderson Mesa,'
but it was pretty marginal.

\Brian
--
See message header for info on list archives or unsubscribing, and please 
send personal replies to the author, not the list.

Other related posts: