Help needed with 10" dob

[bathurst77]

HI.
I was wondering if anyone in or near Blue Mountains NSW would be able to help me with my "Andrews" Dobs.
Ive had it about 18 months and the main mirror has a layer of grime and some specs of crud when i look down the tube, as do the eyepieces.

I would like to remove the mirrors, clean and remount them (and the plossls), but dont know what to clean them with without damaging them, nor do i know how to collumate and align the mirrors.

I will happily pay someones time if they taught me.

I can be reached
jem@jemmex.com.au
thanks
Jem Cullen

[bobson]

Hi

You should read this articles first and if still not sure then someone might be close to you to help you.

Scroll down to Beginners Guides and you'll find about collimation and cleaning your mirror.

http://www.iceinspace.com.au/projects.html

cheers

[bathurst77]

Hi Bob
Yes I had read those, and given that I dont have any collumation tools and have 10 thumbs I thought it would be best to get help from "someone who knows" at least first time!

Rather leave it slightly out of true adn a bit dirty than totally kill it!

[bobson]

Yes, I understand

I had the same feeling when I had to clean my first 8" Dob mirror. But believe it or not everything went fine. I took the side screws off but first marked which way the mirror is sitting. And then carefully took mirror out, together with its cell,cleaned it as described and put it back the same way I marked it. I did not have to collimate it at all after this.

I guess 8" mirror is not that big and thus less chance to move out of collimation, in fact I never had to collimate it. I have 12" now and have to collimate it more often.

You can use film canister (analog camera) as collimating tool. If you don't have one go to shopping centre or chemist where ever they develop photoes and ask for one, they have a lot of them. All you have to do is make a small hole in the centre which is already marked for you. It fits perfectly in the 1.25" but make sure you don't drop it in. You put it in just as you would put eyepiece, tighten slightly and look through the small hole.

You would follow instructions just as if you had collimating eyepiece. You might even find now before you take mirror off that your scope is not collimated.

I used this one for years before I bought laser collimator. I still use it for quick check up of collimation.

bob