Star-testing: My collimation's off by a lot?

[pipnina]

About a week ago in my back garden I decided to try this star testing thing some collimation guides mention. People had suggested that my collimation is off before and I don't have a cheshire or cap to work with (I really need to get one).

Thing is, I can't tell if my collimation is out or not. When I put the 10mm EP in with the 2x barlow to give me 180x magnification, I couldn't see any airy disk or anything, just a point of light with some spikes coming out of it. (not the typical sort.)

But I can say that stars seem to be made of multiple points when I'm near focus, which is meant to be a sign of bad collimation?

I'm going to make a makeshift cap from my focuser's dust cap (I don't use it, I just leave the EP in there until next time :T) If this is bad collimation that should help me out.

    ~pip

[ronin]

I think you can make a collimation cap from a film canister, the old 35mm ones are apparently good.

Try one of the ca,mera shops in Plymouth they likely have a box of the things to be scrapped.

Look up "astro-baby" (Mel).

I think her site has a guide to making and using one, her instructions are well detailed.

I do suggest that you make sure that it is out, it may not be, and also that you know before hand what it is you intend or expect to do.

Collimation makes less problems for visual then for imaging, eye's just are not as critical.

So even if it is out it may not make much difference.

[pipnina]

I think you can make a collimation cap from a film canister, the old 35mm ones are apparently good.

Try one of the ca,mera shops in Plymouth they likely have a box of the things to be scrapped.

Look up "astro-baby" (Mel).

I think her site has a guide to making and using one, her instructions are well detailed.

I do suggest that you make sure that it is out, it may not be, and also that you know before hand what it is you intend or expect to do.

Collimation makes less problems for visual then for imaging, eye's just are not as critical.

So even if it is out it may not make much difference.

I just made the cap. Seems like the collimation isn't out by much if any amount at all. I used the dust cap and some GCSE maths skills to get it on centre. The primary seems framed well in the secondary and the secondary reflection seems quite close to the middle even then. perhaps it's out a *little* because the primary is a little to the bottom of the secondary. I was going to fix this but my alan keys aren't changing the angle of my secondary. I suspected it was missing screws there from the beginning but assumed it used alan keys instead (people here said some scopes do.) Thankfully it looks like it doesn't need adjusting...