Hi Dennis,
I'd say you can easily reach fainter than Nereid going on your last post.
Negative images, for some reson do show fainter stars.
Another method is to take enough images of the field to show a faint minor body and stack them with an offset of the position angle (direction and amount of travel).
Astrometrica will allow you to stack in such a fashion. Offsets and PA should be found in most star software, probably in 'Sky Pro'.
If not try here:
http://www.cfa.harvard.edu/iau/NatSa...atellites.html
I know of no other faint catalogues other than what you are using.
