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Close focus t-adapter alternative

Started by jalbrightx, 03/24/2010 01:49AM
Posted 03/24/2010 01:49AM Opening Post
I've got a very nice scope with one problem - the focuser won't quite reach focus w/a std t-adapter. It's really close, maybe only 2mm off, but it just won't focus. Anyone have suggestions on how to mate a 1.25" prime focus adapter onto a micro43 camera (Lumix GF1) but slightly closer than the std position?

Thanks
Posted 03/24/2010 03:14AM | Edited 03/24/2010 06:26AM #1
Couple ideas:

If its a Newt, you could run the primary
collimation screws in another 1/8 inch or so
-- move the primary closer to the secondary.

You could also get a couple (like 3 or 4) clear or
UV filters, and mount them on the 1.25" inlet.
One filter will push the focus outward by 0.7 to 1.0
mm, so a couple of them should get you the 2mm.
Or find some clear multi-coated piece of glass
from Edmund Industrial Optics -- like 6mm thick
or more -- and put one of those in the path.

I don't know details of the micro43 lens mount,
but you might be able to craft something using
either Baader or Borg plumbing that is shorter.
http://www.hutech.com
http://www.alpineastro.com/eyepiece_adapters/eyepiece_adapters.htm
Which adapter are you using now?

On some scopes the 1.25" inlet can be removed, thus exposing
some threads. Sometimes you can find a way to mate from
those threads on the scope to the camera without the 1.25" stuff.
For example, scope mystery thread to T thread adapter, and
then T-ring on camera.