Alan, I re-read your original post. As mentioned, 80mm binos are BIG, and they require a tripod, or better still an isostatic mount such as a parallelogram mount to view comfortably AND safely.
70mm binos are also fantastic. As I mentioned below, my astro binos are 11X70. I could have gone for 15X70, or 20X80, but went with the ones I did for a few reasons: one, they have a wider field of view being lower magnification, 4.5degrees true field of view; two, they are smaller than the 80's; three, higher magnification binos are much more difficult to hold steady.
My first dark sky experience with them blew my socks off!
Omega Centauri was actually resolved in them! It looked like a fantastically tight pincushion, but the stars were resolved! And the amount of detail of dark nebulosity that totally ripples throughout the entire Milky Way is totally invisible in ALL my larger telescopes. This is something that a rich field scope totally excels at. Even areas of the sky that isn't through the Milky Way still shows oh-so-subtle variations in background illumination. Just stunning. The sketches below were done using my 11X70 binos. The first is of Eta Carina nebula from home in Sydney. The second I did from memory of the area around M8 and M20 and the dark nebulosity that stunned me (I didn't have my sketching stuff with me that night, but the impression it made on my mind I still see crystal clear!).
Some food for thought.
PS, have a look at Andrews Communications. You'll find better prices there, and postage is usually just $10.