Tuesday, June 28, 2011

Bahtinov Mask

One of the biggest challenges I have faced with astrophotography is getting the correct focus.

In the past I have made a hartmann mask to help with focusing and had some success with it.

Recently I came across another focusing aid called a Bahtinov Mask which is similar in function to a Hartmann Mask but resolves some of the shortcomings.

I found a webpage which allows me to generate Bahtinov Masks for various sizes and with some trial and error was able to generate a mask for my DSLR.

I also generated a mask for my C5 but I only cut out the DSLR mask to make sure that my measurements were on the mark.

I used a piece of stiff wire to hold it in place

A few years ago I built an artificial star using an LED and a fiber optic network cable.  It works pretty well, here is an example of what collimating my C8 looks like.

 I figured it would be a good test of not only the feasibility of a DSLR Bahtinov mask, as well as familiarize myself with its operation

Slightly Extra Focus

Slightly intra-focus

In Focus

 The results speak for themselves.  Next step will be to test it under actual use conditions.
I think that a DSLR bahtinov might be not only overkill but slightly un-usable but  I won't know until I give it a shot which probably won't be until this weekend.


1 comment:

  1. I've got one of those. They are a HUGE timesaver for focusing and work so much better than merging 3 blobs together like you would with a Hartmann mask.
    You'll like it! I use mine all the time, works very well when setting up to take images of the ISS flyovers.