35mm Film Canister

[Starjumper]

Hi,

I read somewhere ( cant find the article ) that you can chek the alignment of the secondary mirror using a 35mm film

canister. Does anyone know if this is correct and how is it done.??

Thanks

John

[John]

Hi John,

Here is a link to a web page explaining how it's done:

http://www.galaxypix.com/Stargazing/collimate.html

Hope that helps :-)

John

[PeterW]

The film canister can be used as a cheap 'Cheshire' eyepiece, sight-tube for collimation. Do a search for "Nils Olof Carlin" on Google, he has quite a bit about collimating. A cheshire eypiece is not expensive and does a better job than the film canister. I modded a film canister and chucked it when I got a cheshire eyepiece.

Cheers

PEter

[Starjumper]

John & Peter, thank you for the info and thank you for responding so quickly.

Rgds

John

[philsail1]

"Starjumper"

Yes, Peter is spot on (excuse the pun!).

A "Cheshire" is a very good (and relatively inexpensive) way to check colllimation in a Newtonian, but keep hold of your film cannister - it can be used for a quick check before you set up your scope.

Regards,

philsail1