Pardon me, I should have said "usable field of view". Awful distortion
when off center.

Gen 1 suffers from some distortion at edges of FOV. However, this does not
limit the ability to see in th dark and you mearly center an object when you
want a clearer view. In no way is FOV usability compromised.
When boating you want to see an object to know it's there, not make an accurate
sketch of it. For the purposes of nightime sailing, these inexpensive scopes
are amazing. I suggest that anyone reading here ignore Gary's comments AND mine
and try one for yourself. I was also told the Gen 1's were useless and then a
few sailors proved otherwise when sailing on the LIS. I even tried a pair of
those ancient gen 1 Russian binocs, 15-20 years old I think, and even they were
a revalation.

Capt RB