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Sunshine

First question about Starmaster dob

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Hello, well here it is, my first call for advice, regarding collimation, the chap who owned it mentioned that he collimated it, but when I put my collimation cap In I could see that it looks like the secondary is fairly well but not exactly aligned with the primary.

It is a tiny secondary comparing with my lightbridge, but I can see that two of the mirror clips are visible and the third is just barely in view within the secondary. There is room to adjust as there is dead space available around the visible clips to bring the third clip into view better. I know that messing with secondary mirrors can be a pain, but I wonder what the accepted tolerance is? Should I bother? Aligning the primary is no problem, I have done that steadily with other dobs and newts before.

This secondary has 4 adjustment screws, unlike the 3 on my older lightbridge, if I should adjust, would this method be ok? Ever so slightly loosening all 4 screws, moving the secondary very gently by hand (without touching the mirror of course) then once in place and all 3 clips are visible, re tighten all 4 screws evenly while keeping the secondary in its position. This would save messing around with one at a time back and forth, theoretically this method should work no?

i realize I haven’t first lighted it yet, I’m just picky and would like to start with the scope as best as it could be, thanks to all!.

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Based on your description, I suggest you leave the secondary mirror alone. Just ensure the primary mirror is adjusted then enjoy the views.

Jason

 

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My scope has 4 finger adjustable screws too (it's an Astrosystems secondary holder, with extended thumb screws) - I adjust the diagonally opposite ones in pairs: loosen one a smidgen, tighten the diag opposite one.

I use the barlowed laser method, and it works very well, less than 2min in the dark to collimate the scope.  I did even take the controversial step of dotting my secondary, but many people will revolt against that!!

There are more rigorous methods, but fwiw this works for me and my low fuss threshold.

I collimate every time I use the scope, sec + prim mirrors.

Edited by niallk
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5 hours ago, Jason D said:

Based on your description, I suggest you leave the secondary mirror alone. Just ensure the primary mirror is adjusted then enjoy the views.

I think I’ll do just that, thanks!

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4 hours ago, niallk said:

did even take the controversial step of dotting my secondary

Dotting the secondary?? Wow that’s new to me, I trust it helps but I’m not sure i would do it.

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