Collimation Without Tool

[the milster]

Is it possible or do I really need to buy one? I think the wife is gonna blow a gasket if I spend any more money

[Rigel-7]

You can use a 35mm film canister lid with a hole drilled in it, star collimation is free, a cheshire is £25 - I think Astro-Baby did a nice article on Collimation without lasers - a google would be worth a try...

[Stagman]

Is it possible or do I really need to buy one? I think the wife is gonna blow a gasket if I spend any more money

What type of scope is it?

[the milster]

130 newtonian.

I've tried you tube and they all seem to use a laser or a cheshire.

[Rigel-7]

You can use a 35mm film canister lid with a hole drilled in it, star collimation is free, a cheshire is £25 - I think Astro-Baby did a nice article on Collimation without lasers - a google would be worth a try...

Using a collimation cap (35mm film can lid)

[Mr Q]

Yes it is.

Aim your scope at a bright star near the zenith, then rack out the focus till you see a big ball of light with rings of light and dark with the secondary shadow in its center. These rings should be concentric in the ball of light. If not, adjust ONE mirror cell alignment screw/bolt (not a mounting bolt) about a quarter turn, then recenter the star in the field of view. If the rings get more concentric, repeat the process with turning the adjustment a bit more in the same direction. If the rings get worse, go back a quarter turn, then another. You may have to do this to each adjuster in severe colimation mis-alignments but usually, with a tweek of each adjuster, you can get the colimation as close as you need to.

Generally, the secondary mirror does not need any adjustments, unless it has been altered.

There are a few web sites with diagrams of the above steps that can help you see what you are doing.

Bottom line - a good colimation is possible without any tools or special equipment once the procedure is learned and a quick "out of focus" star test can keep tabs on any future adjustments needed at each observing session.

[AndyH]

I second, the film canister method. This'll get it pretty close, then do a star test for fine adjustment.

[smolloy]

Have a search around this forum. There were a couple of threads here that really helped me, and I did it with no extra equipment.

Instead of buying something, I made myself a collimation cap from a dust cover for scope. There was a mark in it that showed me the exact centre, so I used the smallest drill-bit I own (absolutely tiny) to make a small small hole in the exact centre of it. Then, on the part that will be inside when I attach it to the scope, I glued a small metallic washer so that the tiny hole was right in the middle.

The point of the washer is to make it nice and clear where the hole is when you're looking at its reflection. Then just follow the instructions you find online for collimating with a collimation cap.

I was absolutely petrified of getting something wrong, but in the end it was laughably easy!! Just take sensible precautions, like making sure the scope is always pointing slightly downwards so that any dropped tools don't fall onto the primary mirror. Also, think about what would happen if the washer wasn't stuck properly, and fell off into the scope during the process.

Just be careful, and slow, and it'll be fine

Let us know how you get on.

Steve

[the milster]

Ok, cheers people, I'll try to get hold of a 35mm cap tomorrow and see how I get on.

I'm not even sure if it out but I dropped it yesterday, only from a few inches but I want to check.

[Mr Q]

This site can help you without using toolsHow To Collimate Your Newtonian Reflector - Do It Yourself - SkyandTelescope.com