Bahtinov Mask Generator - Anyone made a working one?

[OzDave]

Hi,

I've had a go at making a Bahtinov Mask using this website:

astrojargon - Bahtinov Focusing Mask Generator: Version 0.4

The one I tried was for my SkyMax 127 Mak. I found that it sort of worked, but the diffraction pattern wasn't really like the example images seen in tutorials on how to use the masks. The net result was that focusing wasn't really any easier with the mask compared to without.

So I'm wondering if I just made it wrong, cut it out wrong, applied it wrong, or maybe DIY masks just aren't very good generally compared to say a machined metal one.

The one I made was cut from thin cardboard, like postcard thickness.

Has anyone got any success stories (or failure stories) with DIY Bahtinov Masks?

David

[Bizibilder]

http://stargazerslounge.com/diy-astronomer/118816-simple-bahtinov-mask-construction.html

Will take you to details of "one I made earlier"!! It works very well.

[Rob_Jn]

I used the templates here:

http://www.focus-mask.com/Free_Templates.html

and cut one out of thin gauge aluminium for my 14", seems to work fine the couple of times I've been out and used it. Most people seem to say the exact dimensions aren't critical? One thing I noticed is that I need a fainter star on the 14" otherwise the pattern is overexposed.

Rob.

[astromerlin]

I needed a way to focus my finder/guider so I made one by printing the image obtained from an online source onto clear film and using a cap off a spray can cut the top off and glued the film on. The cap was a bit of a loose fit but but the mask worked as it should.

Havn't done one for my 10" though..

[Beyond_Vision]

Can you post an image of the diffraction spikes?

[OzDave]

Can you post an image of the diffraction spikes?

I could but it'll take me a while for various logistical reasons. I think based on others responses that i'll have a go at making another one and see what happens. If no good i'll grab an image.

[Dave]

Hi David

Here's what it should look like:

http://www.eagleseye.me.uk/SGL/BahtinovFocussing.avi

This video was taken using a Webcam on Capella with a 10" Newtonian.

This mask is made by printing on photo paper, laminating and then cutting the slots out.

Always use a bright star to focus the camera/webcam first.

The Bahtinov mask has really made my focussing so much easier.

Down from almost an hour of frustration to a few minutes now to get it spot on.

Dave

[OzDave]

Thanks Dave, that was a useful video. I'm going to give this another go with a more sturdily constructed mask.