How to choose a good diagonal?

[Ales - iStar Optical]

Aug 1, 2014 3:40:09 GMT -5 mrkellytaylor said:

I can highly recommend the Istar's diagonals.
see my review on Istar website.
when seeing allows it will show you what your optics will pass.
it will be one less thing to worry about. get one and have fun.
I bought 5 five of them so far. everyone that tried them won't give them back.
Great product!!

Mr. Kelly Taylor

Thank you Kelly! We appreciate both your business and your comments about quality of our diagonals. Im only having hard time understanding one thing though. Our diagonals are sold by dozens only at STARIZONA (a well known retail shop in Tucson run by Dean), but NOWHERE ELSE. More people should look into this product and compare with ANY competition. Our diagonals were tested against the best, 400 to 500 dollar diagonals produced by the Big names, and none tested better. We might generate more interest by doubling or tripling our price.. but WHY!

Regarding the coating, we use SiO2 hard coating on our diagonals AND all of our lenses too.

best regards,

Ales

[Steven C]

May 21, 2014 7:15:32 GMT -5 rgm said:

I agree with everyone else. It is very difficult to see differences in mirror diagonals. I can though, see small differences with prism diagonals. I find slightly less scatter with prisms in my refractors. A prism also allows me use binoviewers without an OCS due to the shorter light path.

I find that on bright objects (Moon, Planets, Solar, etc.) the prism definitely gives the better contrast over a mirror. 

When I am in truly dark skies I find the first surface mirror diagonal provides improved brightness for dim objects.