Is Celestron cheating us with their binoculars ?

[skysurfer]

The Skymaster 15x70 has actually 65mm aperture, revealed by me (and others) with the flashlight test: focus to infinity, put a ruler a few cm in front of one of the objectives and hold a flashlight a few cm behind the eyepiece. This will reveal the actual objective diameter.
The Skymaster turns out to be only 65mm, but the price of $130 is also not a price for which you can expect much.

But the more 'premium' Echelon 16x70 of $1000 turns out to have the same issue: objectives stopped down to 65mm and for such a price it is a cheat

https://www.cloudynights.com/topic/5...iewcomparison/

[bigjoe (JOSEPH)]

Originally Posted by skysurfer

The Skymaster 15x70 has actually 65mm aperture, revealed by me (and others) with the flashlight test: focus to infinity, put a ruler a few cm in front of one of the objectives and hold a flashlight a few cm behind the eyepiece. This will reveal the actual objective diameter.
The Skymaster turns out to be only 65mm, but the price of $130 is also not a price for which you can expect much.

But the more 'premium' Echelon 16x70 of $1000 turns out to have the same issue: objectives stopped down to 65mm and for such a price it is a cheat

https://www.cloudynights.com/topic/5...iewcomparison/

Theses things happen with quite a few brands..Even scopes... the 127mm Mak primary mirror is about 120mm actually, but still performs brilliantly with Schott glass...what can you do though.

bigjoe.

[Slawomir (Suavi)]

Although 65mm is only a few% less than 70mm in diameter, but in terms of surface area and thus light gathering the difference is about 14% less, which is significant.

[Atmos (Colin)]

Originally Posted by bigjoe

Theses things happen with quite a few brands..Even scopes... the 127mm Mak primary mirror is about 120mm actually, but still performs brilliantly with Schott glass...what can you do though.

bigjoe.

If the front lens on the Mak works as a lens you don't need a 127mm primary mirror as long as the front aperture is 127mm diameter.

[bigjoe (JOSEPH)]

Originally Posted by Atmos

If the front lens on the Mak works as a lens you don't need a 127mm primary mirror as long as the front aperture is 127mm diameter.

Indeed corrector is 127mm..

Those light rays diverge past the secondary baffle in these due to that thick meniscus , and dont cause the obstruction you would think in these Maksutovs.

Usually the primary should be at least the size of Corrector ..but this is a moot point, as optics in these are really superb.
bigjoe