Camera Adaptor

[GeoffK58]

Hi all,
I have an Olympus eM10 (micro four thirds) and an old 4" Newtonian reflector that takes 1.25" eyepieces. I want to have a go at some lunar photography, for a start, and need some advice on what type of adaptor(s) I need to do prime focus photography. In a different forum (photography) it was suggested that I may have a problem with being able to reach the right focus point.

Any comments and advice are most welcome
Thanks

[raymo]

First, take your Newt outside during the day, remove any eyepiece;
remove the lens from the camera, and hold the camera up a few centimetres from the focuser tube, rack the focuser fully in toward
the tube and move the camera closer and closer to the open end of the focuser tube. If the lens mounting face of the camera comes
into contact with the focuser tube and the camera has not reached focus, then the scope is not designed for imaging. If it is obvious that it has nearly reached focus you might be able to fit longer collimation screws to the primary mirror, and achieve focus. If it is still quite a way from focus you would need to move the primary mirror further up inside the tube.
If you can reach focus with the camera at least 10mm from the focuser
all you need is the appropriate T-ring for your camera and your'e off and running.
raymo

[vaztr (Andrew)]

Hi Geoff,

If you can't reach focus directly you could try a Barlow between the scope and the camera this can help but does 'double' the F of the scope

VAZ

[GeoffK58]

Originally Posted by vaztr

Hi Geoff,

If you can't reach focus directly you could try a Barlow between the scope and the camera this can help but does 'double' the F of the scope

VAZ

Thanks for this advice. Do you have specifics on the adaptors that I will need
Geoff

[GeoffK58]

Originally Posted by raymo

First, take your Newt outside during the day, remove any eyepiece;
remove the lens from the camera, and hold the camera up a few centimetres from the focuser tube, rack the focuser fully in toward
the tube and move the camera closer and closer to the open end of the focuser tube. If the lens mounting face of the camera comes
into contact with the focuser tube and the camera has not reached focus, then the scope is not designed for imaging. If it is obvious that it has nearly reached focus you might be able to fit longer collimation screws to the primary mirror, and achieve focus. If it is still quite a way from focus you would need to move the primary mirror further up inside the tube.
If you can reach focus with the camera at least 10mm from the focuser
all you need is the appropriate T-ring for your camera and your'e off and running.
raymo

Raymo, thanks for this I will give it a try

Geoff

[raymo]

He could do that Geoff, but at 1200mm f/10 he would have a very slow setup,
and be limited to pretty short unguided subs, so only the very brightest objects would be viable. If he could find one a 1.5x Barlow would help.
raymo