And you need to ask yourself how would someone writing a review really know this unless they were just repeating some marketing gibberish? The best one could do is say that they measured the transmission and speculate as to why they might be different. It could be true but how would anyone in our position really be able to know that and state it as fact?
every reviewer has said the BCOs use newer, superior coatings than the original BGOs.
I have the 10 and 6mm BCO for testing purposes. I still haven't taken them out to dark skies yet...to validate them. The BCOs seems good so far
I also got the Barlow...I'm not so confident of it so far. I hope it is just a bad copy.
I used them with my 22" f/4 reflector, Tak TOA150 6" and 4" f/11 achromat in my front yard just looking at stars.
I need more time before I pass judgement on these eyepieces.