Barlow, DSLR and ED80 - can't find focus

[niko]

Hi all,

the other night I attempted to connect my DSLR to the ED80 with the barlow in the imaging train.

I couldn't find focus and wonder if I need to shortern or lengthen the image train to achieve it.

I currently have DSLR, T-ring, t-ring to 2" tube and 2" extension tube. I connected the barlow after all this and before the scope.

Any help greatly appreciated

many thanks

niko

[pluto]

I had the same problem, I bought a 2" 50mm extention tube and now I can get focus.
I could see the image getting sharper the further I out I moved the focuser so I knew I needed the camera to be further away. I have an ED80 and a 5DmkII.

[niko]

thanks Hugh. I already have the extension tube in the set-up so I wonder if I need a longer one or another one...?

[Larryp]

Hi Niko
I have an NG 102 triplet, and I can just get focus with a 50mm extension tube with the focus racked right out, so I run it with a 50mm extension and a 35 mm extension together. Thats with a 4x Powermate with the extension tubes between the Powermate and the focuser.

[niko]

thanks Laurie

so it would go

camera, t-ring, barlow, extension tubes, focusser...?

[pluto]

My setup is-
T-ring to one of these:
http://www.bintel.com.au/Astrophotography/Adapters/Bintel-Camera-Adapter-2-/35/productview.aspx
then a 50mm spacer like this:
http://www.bintel.com.au/Accessories/Extension-Tubes/Bintel-Extension-Tube-50mm--2--/415/productview.aspx
then the barlow into the focuser (I think, I haven't used it in a while, I may have the extention tube after the barlow but I can't remember).

[Larryp]

Yes, Niko

[jjjnettie]

LOL I slotted in the 4x powermate into my RC8 last night. My total image train was over 12" LOL It looked ridiculous, but it worked and was still reasonably sturdy.

[Larryp]

My imaging train looks just as ridiculous