I imaged Omega Centauri (NGC 5139) last night with my LX200 8" and a
SAC-7B camera. Now I would really like to determine the magnitude of
some of the dimmer stars in the cluster. Funny thing is, it appears
Cartes Du Ciel and Starry Night Pro both cut a rectangle around any
NGC object and display no stars there. That rectangle pretty well
matches my camera field of view.

Obviously I don't expect to find a map of the millions of stars within
Omega Centauri, but does anyone know of a way to at least identify
them down to, say, Mag 13 or 14?

Go to the SIMBAD's Aladin site

http://aladin.u-strasbg.fr/aladin.gml

and start the Aladin applet. Click the "Load" button and type
"NGC5139" into the "Target" box. You'll be shown a list of
digitized images. Select the "SERC J(optical B) 1.7x1.7" image,
which has a wide field of view. Double-click on that item
in the list. You should see a picture of the cluster appear
on your screen. Now choose the "Surveys in Vizier" item on
the right side of the "Server Selector" window. Highlight
"USNO-B1" and click on "Submit". An overlay of markers should
appear on the image, indicating all stars in the USNO-B1.0
catalog which appear in the image. Clicking on any marker
will give you information on that star.

Aladin is a terrific tool, and it's free for everyone
to use.

Michael Richmond