Re: Collimating the dob
- Hello Max..
I'm glad all this came up. I've looked at the peephole diagram you cited and have a question.
What's shown in the diagram is what I see through my peephole with one exception. The reflection of the main mirror is not centered in the secondary. Everything else within the reflection of the main mirror is all lined up and the secondary is centered in the focuser.
I haven't had a chance to star test the scope, and was just wondering what adverse effects, if any, this configuration would produce.
TIA very much,
--- In skyquest-telescopes@y..., Max Fisher <klaman7@y...> wrote:
> As for the orion collimating instructions put them in the nearest bin then check out http://www.zebu.uoregon.edu/~mbartels/kolli/kolli.html its a bit technical but the part titled 'The Peephole' (its about 3/4 down the webpage) should make things a lot clearer
- --- In skyquest-telescopes@y..., "pasushkopa" <pasushkopa@y...> wrote:
> What's shown in the diagram is what I see through my peephole withone exception. The reflection of the main mirror is not centered in
the secondary. Everything else within the reflection of the main
mirror is all lined up and the secondary is centered in the focuser.
>wondering what adverse effects, if any, this configuration would
> I haven't had a chance to star test the scope, and was just
> TIA very much,
You SHOULD try to get the reflection of the primary centered in
the secondary. You will have to adjust the tilt screws on the back
of the secondary spider to do this. But read some of the suggested
collimating instructions (even the one from Orion, which is OK for
THIS step) first.
What you lose, in your present configuration is, possibly some of
the light coming from your main mirror (depending on how far off
center your reflection of the primary seems to be) and also possible
distortion arising from imperfections at the edge of the secondary.
(When the image of the primary is centered in the secondary, none of
the light reaching your E.P. will have come from the very edge of the
There has been an AWFUL lot of talk recently on many of the forums
regarding collimation and how difficult it is to do properly. Read
any of those threads and notice how often the experienced guys tell
you NOT to be afraid of the job: you won't screw up anything you
won't be able to get right again later. Listen to them. It doesn't
have to be done with brain surgery-like precision, and every step you
take towards proper collimation will pay off. When you find out that
the added steps no longer are worth it, you'll know that you are now
being limited by things like atmospherics and the inherent quality of
your set up. But RELAX!!