a dim witted astro question

[graham.hobart (Graham stevens)]

Hey Guys and gals, if I change the focuser on an f4 newt from the standard issue to a moonlite, does it affect the collimation? I mean- when you buy the Cats Eyes tools it goes into how far the focuser is out etc and the Moonlite is a lower profile than the stock focuser?
Or do I just suck it and see and adjust accordingly anyway?
I don't want to mess with the collimation unless I really really have too.
Sorry for the thick question but my brain hurts from all this rain!
Graz

[rustigsmed (Russell)]

congrats with the moonlite purchase - great investment!
I have one on my imaging newt, think I should look into getting one for the dob - electronic focusing is soo much easier.
do your best to centre the moonlite (not sure you have much choice), it shouldn't but it perhaps could if the middle of the focuser ends up slightly off centre (from the secondary).

[graham.hobart (Graham stevens)]

Hi Thanks for that- yes I am hoping that the adaptor kit I got slips right into the holes so it automatically centres it- I really don't want to be drilling into the OTA just yet.

[el_draco (Rom)]

Originally Posted by graham.hobart

Hey Guys and gals, if I change the focuser on an f4 newt from the standard issue to a moonlite, does it affect the collimation? I mean- when you buy the Cats Eyes tools it goes into how far the focuser is out etc and the Moonlite is a lower profile than the stock focuser?
Or do I just suck it and see and adjust accordingly anyway?
I don't want to mess with the collimation unless I really really have too.
Sorry for the thick question but my brain hurts from all this rain!
Graz

Dopey bugger... should have asked me. The issue will be around the size of the light cone leaving the side of the scope and the profile of the inside of the focuser. Lower profile can means more back focus but it will depend a bit on the diameter of the cone as it enters the base of the focuser... dont want to loose light due to obstruction Happy to do the math for you mate...

Rom

[codemonkey (Lee)]

Not a dim-witted question Graham, or if it is, then I'm in good company because I was just about to ask the same question myself. I'd swapped my stock focuser on an ED80 for a moonlite without a hassle, but I wasn't sure if it would affect collimation on my RC8.

[graham.hobart (Graham stevens)]

You see that's the type of answer I was hoping for- at f 4 your have a really tight light cone.
Anyway back to my experiences.i reckon it took me nearly four hours to fit the moon lite as the universal adaptor was that,- and the screws with washers are tiny, like 2mm or something , and my hands are big and sweaty. And I was nervous, trying to get it all central and stuff.
Anyway, got it on, and roughly checked collimation both with a sight tube and a decent quality laser. Seems to be an off set with the secondary .
I'm really inclined to leave everything alone till I can star test it as, I have advanced experience in patience, plus I have been looking on line and reading and it seems to me that even at f4 ( at 800mm) you could expect less than a few mm of offset so my my low standards I should be rinky dinky !!
can't wait for those big spikey stars -I just love diffraction spikes!!
Graz

[graham.hobart (Graham stevens)]

El Draco . Last time I asked you anything it turned into a few hours long conversation. And you introduced me to Drambuie. For that I will be eternally grateful.