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Afocal
Hello,
I currently own a nice 12inch Dobsonian which is superb for visual work. That is if you can keep it collimated.
I haven't had much luck with prime focus photography. The focus is just a bit short of the prime focus I need.
If I mess about with a Barlow lens and shorten it, I suppose I can get to work be it magnified. I have tried this approach on other scopes and it seems to work quite well. Be it the cost of the Barlow (hmmm I might still go with this idea).
I am tinkering with Afocal photography. If find it near impossible while using my 2in eyepieces. However using my humble 13mm 1.25inch Plossl and a short extension tube it works great.
I don't completely understand why it doesn't work with my 2inch eyepieces. Even my 42mm eyepiece projection eyepiece has trouble focusing. I set the projection to short or as long as possible and it still has trouble focusing. Same deal for my 28mm.
As I said I am somewhat confused why it works so well with my humble Plossl. I thought Afocus was about as simple as it gets. You should be able to simply hold a camera up to the eyepiece. However I seem to have trouble sometimes.
Not sure what I am doing wrong. The projection eyepiece is focused for visual work. Looks absolutely brilliant with such a wide field of view. Then I attach a short tube and the camera. No lens on the camera and I can not focus the Afocal image in the camera.
However I do the same thing with my 13mm Plossl it works beautifully. Be it a bit dim but still working fine.
Any ideas on what is going on. Am I missing something?
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