Jump to content


Bahtinov Substitute


Recommended Posts

Any thoughts on this: I'm not sure where I came across it, but somewhere on the web I read that someone had cut out the blanked off hole on the dust cover of an 8" newt. With the main cover in place and the cap taken off the second small hole the scope gives a double image when aimed at a star. These apparently merge into a single image when brought into focus. Sounds like a good idea if it works, but I though it was worth checking out before I get the craft knife out - anyone tried it?


Link to comment
Share on other sites

It will be behaving like a hartman mask I always found it quite difficult to determine the exact point where the two images merged...

Have you looked at the simple Y mask as an alternative to the Bahtinov?

much easier to make...

Edited by Psychobilly
Link to comment
Share on other sites

That's otherwise known as a Hartmann mask, or a variation of it, and was generally used until the Bahtinov mask was introduced. It works, but not as well as a Bahtinov.

Edit: Sorry, repeating what Psychobilly said. Overlapping posts.

Edited by lukebl
Link to comment
Share on other sites

Interestingly, the bahtinov mask I use on my C9.25 also works for an MN190 and also an F4 8" newt.

Other than having a bahtinov mask that gave you a fiver every time you use it I cant see how it could be any better :)

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.