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1st impression:Celestron Skymaster 20x80 binocular

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#1 cirrus1500

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Posted 20 July 2013 - 12:36 PM

I notice that while there are regular new posts of the Skymaster 15x70, there aren't many recent reviews or reports on the Skymaster 20x80 (not found a review or first light report for the last 2 years in CN). I just got mine so I might as well share a little of my first impression about it. Previously, there are lots of negative comments about this model's collimation and so I am not sure if QC for the later lots are still so poor or not. I went ahead and bought it anyway because I couldn't resist the idea of getting aperture of two 80mm scopes for $100. As for the potential collimation problem, I intend to learn how to fix collimation if I have to, an opportunity in itself :).

I currently have an Orion Scenix 10x50, (which cost 50% more despite its smaller size) and so that's all I can compare it with. The sky is very cloudy tonight and the only object that is visible through the clouds is the waxing gibbous moon. It is not of the best condition but I just do not want to wait for another day to start using it.

The Skymaster is heavy (2.2kg) so I mount the bins on a Slik Pro 500DX tripod with a quick release head attached to each bin. The SkyMaster's rubbery grip feels fine, except for the lower part where I place my thumbs is made of very thin rubber that bulges in and out as I press onto it. It feels like it will tear after not too long. The Skymaster comes with a built-in metal tripod adapter and it attaches firmly to my quick release. When mounted onto the tripod, it feels very firm. The adapter also allows me to choose how far front or back of the Skymaster to attach to the triod (I guess this help balance the bin better for different altitude viewing angles).

The moon looks to have about the same clarity though both the Scenix 10x50 and Skymaster 20x80 (I can't say the views were bright and crisp because of thick cloud cover). The SkyMaster do not seem to have any problem with the collimation (a single moon image, can see the craters, clear termination details, no headache) and the views was pleasing enough given the conditions. I notice some very slight greenish/blueish colors on the bright edge of the moon, and the position of the colors change depending on the viewing angle. The CA effect is very thin and doesn't bother me at all (YMMV).

As for viewing comfort, I notice that when viewing through the Scenix which has an eye relief of 13mm, I am able to wear glass and still see the entire field of view. But for the SkyMaster which has an eye relief of 18mm, I need to take off my glasses and press my eyes on the cups to see the entire FOV. So the eye relief specs of the SkyMaster may not be accurate here.

Before I can do more observation, more clouds rolled in and obscure the whole moon and there's nothing left to test on. I feel that I probably received an acceptable SkyMaster and I hope it will hold its collimation in the long term. By the way, my SkyMaster 20x80 version is 71018. Will update when I have the chance.

#2 GlennLeDrew

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Posted 20 July 2013 - 12:54 PM

At least some of the chromatic aberration you describe is lateral color introduced by the eyepiece.

Eye relief is technically the distance between the *surface* of the lens and the exit pupil. If the lens is recessed, the *useable* eye relief shrinks accordingly.

#3 cirrus1500

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Posted 20 July 2013 - 01:09 PM

Eye relief is technically the distance between the *surface* of the lens and the exit pupil. If the lens is recessed, the *useable* eye relief shrinks accordingly.


Hi Glenn. I think you are right. I just noticed that the eyecups of the SkyMaster is deeper than the Scenix ones (effectively recessing the lens). And I forgot to fold them when viewing with my eyeglasses :foreheadslap:. That may explain why I did could not get close enough to see the full FOV. Anyway for the Scenix, I did not have to fold the eyecups and I can still see the full FOV and that's how I got use to not folding the eyecups.






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