Porro prisms, Bak4 glass, center focus, light weight (2 lbs) - all what ytou are looking for in astronomy AND 8.5 degree field (usual binoc field is 5 -5.5 degrees). I use these as my "grab and go" instrument for astronomy, in a lawn chair. Excellent for the experienced amateur and the best introduction to learning the sky and star-hopping for the neophyte.
The only reason that these binoculars did not get five stars is the focusing mechanism for the right eye. It is hard to turn, it should have been made with a more solid material. Otherwise, wow! Great optics, the field is magnificent and sharp. Great for sweeping the Milky Way. Do I recommend them? Yes, but ***** should take care of the eyepiece problem.