Hi Lester
I use the on-line USNO Flagstaff Station Integrated Image and Catalogue Archive Service search at:
http://www.nofs.navy.mil/data/FchPix/
Basically, you enter the RA and DEC coordinates of the centre of the field and the size of the field and a plot is displayed (or e-mail link provided) which show stars down to at least mag 21.
Remember to set the correct epoch, I use J2000.
Cheers
Dennis