This is proving to be quite an informative discussion. I found an interesting write up on “
Focusing Methods for Astrophotography” on the website of Jerry Lodriguss. Out of the 17 methods of focusing that he discusses, he lists the eye as the least accurate method whilst the Bahtinov Mask only comes in at #6, with the Hartman Mask a lowly #4 on his list. The low ranking of these masks surprised me!
Using Software Metrics was judged to be the most accurate, placed at the top of the list at #17.
I haven’t copied the ranked list, as Lodriguss’ website prevents this via his copyright statement, so here is the
link to the write up. Well worth a read. I hadn’t realized that there were so many methods of focusing, although I guess we should now add the Bahtinov Grabber and the
Carey Mask derivative of the Bahtinov Mask, making the list 19 long!
Cheers
Dennis