Night Vision Distance between day optic and clip on.

[Choid]

So, is there a rule of thumb on this? On my PVS-30 I have always tried to get them as close as possible, then wrap, but on the instructions for the pvs 27, it shows that they should be basically an ocular cap distance apart, then wrap. I assume this is actually critical, because lenses, but I am not sure which is actually correct. Info please.

 

[jeffl838]

I think it's because it's a marine corps product and god forbid you take that cap off