Offset aperture mask


Jeff Allegrezza
 

One thing I enjoy about this hobby is "tinkering" with my equipment.

I had a fantastic time last night making a simple 3 inch offset aperture mask for my 10 inch dob to view double stars. You experienced visual observers will have discovered this years ago, but I thought it might be useful to mention for other new folks.

It might have been the interaction of lower brightness and the astigmatism in both of my eyes, but doubles like 59 Andromedae and 65 Piscium looked great with the mask.

I got the idea here:  


Mark Copper
 

Hi Jeff,

There is lots of fun to be had with masks. Mel Bartles is an expert for sure.

What material did you use to make your mask?

Here is a link Wallace told me about for focusing masks: https://www.bay-astronomers.org/TM/FOCUSING%20MASKS.pdf

And here is a link to a JDSO article on diffraction masks to help view double stars with large delta mag: http://www.jdso.org/volume11/number1s/Foley_343_360.pdf

And you can use a hartman/scheiner mask for out-of-focus seeing measurements.


Jeff Allegrezza
 

Thanks for the links.  Looks like some interesting reading!

For material, I cut up a cardboard shipping box that was sitting in my garage.  I happened to have a 3 inch drill bit so it was easy to make a nice circle.

Jeff


On Fri, Oct 8, 2021 at 10:09 AM Mark Copper <mlcopper@...> wrote:
Hi Jeff,

There is lots of fun to be had with masks. Mel Bartles is an expert for sure.

What material did you use to make your mask?  Those both lo

Here is a link Wallace told me about for focusing masks: https://www.bay-astronomers.org/TM/FOCUSING%20MASKS.pdf

And here is a link to a JDSO article on diffraction masks to help view double stars with large delta mag: http://www.jdso.org/volume11/number1s/Foley_343_360.pdf

And you can use a hartman/scheiner mask for out-of-focus seeing measurements.