Barlows and DSLR prime focus

Lee · #1 20-08-2006, 12:06 PM

After my first foray into some solar imaging yesterday, I want some more image scale!
If I add a Barlow to the focuser, I assume I can shoot through this with the DSLR - the question I have is, will this muck around with the focal plane to the point where getting focus with the DSLR is impossible - as it is with the Dob.....

Equip - ED80, D70....

Any suggestions on Barlows to use? What difference to the focal plane does a Barlow generally make??

Cheers all....

[1ponders] (Paul) · #2 20-08-2006, 12:10 PM

You should be able to get to focus. I can't recall trying it with my ED80 but my Celestron 102 has np reaching focus with barlow attached to camera and straight into the focuser. If it does case problems try it with a star diagonal in place.

gbeal · #3 20-08-2006, 05:37 PM

It should work, although I do notice that there is a difference between the 2.5x Powermate, and the 5x Powermates that I use. With one of them (and a ToUcam, not the DSLR) I find I need an extension to take the whole system "out" slightly. Try it and see.

Lee · #4 20-08-2006, 05:48 PM

That doesn't sound too bad - if it has to come out, I can live with that - if I lose in-focus its a harder problem.....

Would a barlow in my Newt help me get prime focus with an SLR???

gbeal · #5 20-08-2006, 07:06 PM

Maybe, but if it is similar problem to one that someone else posted a week ago (can't think of the exact post offhand) then my feeling is get the focus sorted, without the barlow. I did toy with using the likes of the relay lens system that my Denkmeir bino viewer uses, but in the end opted for a shorter focuser, and upped the mirror slightly, in the tube.

Striker (Tony) · #6 20-08-2006, 07:58 PM

I couldn't get enough outward focus with the 1.6x barlow with a canon 20DA and ED80.