new star diagonal for achromatic
Posted 15 November 2012 - 08:07 PM
so the 1.25" diagonal in my used xlt 102 is all scratched up on the tube and slips around too easy.. I bought an orion dialectic 99% for my sct and am happy wi it. I was planning on getting an orion 2" 99% reflective dialectic coating right angle as a replacement so ill have flexibility with 2" or 1.25" eyepieces. the price is right the specs are right , just want to see if I might be missing anything before I get it.. ie: are any of the other brands worth twice the cost? any certain features good for this type of scope? should I get a 45 deg instead of 90 deg? just want to make sure I get the right thing.
Posted 15 November 2012 - 09:51 PM
I bought a 1.25" 90 degree Williams Optics from Agena and it meows like a happy kitty cat. I think you're good with the Orion, though!
Posted 15 November 2012 - 10:04 PM
Posted 16 November 2012 - 05:38 AM
Without a doubt get a 2 inch 90 degree. Enhanced or dielectric should be fine. Suggest one with a compression ring vice just a screw. should be $100-150 if you go dielectric. The GSO ones are $100 at AgenaAstro.
A 2 inch diagonal is definitely worthwhile, with the right eyepiece it'll provide a 2.4 degree field of view in an 4 inch F/10. GSO makes them for various vendors, Agena is a good place to buy.
As far as the 45 degree diagonal, these are correct image diagonals and use a complicated roof prism that has a complicated light path, at high powers they are generally perform poorly.
Posted 16 November 2012 - 07:38 AM
Jon you are talking about the gso's using the prism right? the orion doesn't say that and I assumed the dielectric coatings was specifically for mirrors which offered more light transmission than prisms I thought I read. the orion doesn't say anything about being correct image and neither did the 1.25" version of the same thing.. YET I found it provided a right side up image but was still reverse... but dialectric mirrors and no prisms.. so once again my questions have questions. ?
so I did just see the Williams which has all the same features at about the same price 135. might try that one..actually a couple dollars cheaper than the orion. if it doesn't say I thought I'd assume its not correct image, (?)
on the agena site I see that all the "correct image" diagonals are prisms so that makes sense.
regarding the 45 vs 90* question, yes I setup the scope Sunday night I think It was and didn't extend the tripod legs (habit from using the C10 reflector) and yes I was literally on the ground a lot.. I'm just getting used to all this new stuff.. thought it'd ask just in case there was something else I didn't know I didn't know.
Posted 16 November 2012 - 08:06 AM
would I notice the quartz quality with this achromatic refractor ?
would I notice it if I later upgraded to an APO refractor? (I know, that's crazy talk.. what! me? upgrade? )
thanks so much !
Posted 17 November 2012 - 11:35 AM
Posted 19 November 2012 - 05:01 PM
Posted 19 November 2012 - 10:20 PM