Where and how to get the USNO catalog?


I’ve been shooting galaxies with a 2x Powermate that increases my focal length to 2000mm. My meridian flips have been failing to plate solve with the GSC catalog I’ve been using at 1000mm fl. I think I need to switch to a deeper catalogue like the USNO. First, am I correct that the appropriate catalogue is USNO-SA2.0 (rather than the USNO-A2.0 which is about 10x larger)? Second, I’m having trouble downloading this catalogue using the instructions at http://www.nofs.navy.mil/projects/pmm/sa.response. It directs me to go to ftp.nofs.navy.mil and login with “anonymous” then to put in my email address as the password, but when I do so the login control just reappears and re-asks me for my login credentials. Am I doing something wrong? Is there an alternate site to get the catalogue?

thanks, Keith


This might help you a bit (you want the 6 GB USNO A2.0):


The general rule of thumb is:

  • Images greater than 15’ across: use GSC
  • Images less than 15’ across use USNO
  • Never use UCAC4