topic Re: EOS M100 and sharp focus with a telescope in EOS DSLR & Mirrorless Cameras

EOS M100 and sharp focus with a telescope

jfsestito — Thu, 15 Oct 2020 12:01:36 GMT

Hello. Long time astronomy fan, but new to cameras and astrophotography.

Learned how to change settings, (shutter release w/out lens, ISO, exposure time), but am struggling to get a sharp focus. Stars and planets are blurry.

Canon EOS M100 attached to a Meade LX90 (8" SCT/ 2,000mm focal length).

Any suggestions would be appreciated. Thanks in advance.

Re: EOS M100 and sharp focus with a telescope

kvbarkley — Thu, 15 Oct 2020 13:30:59 GMT

How are you attaching it? Normally the focus is all in the telescope.

Re: EOS M100 and sharp focus with a telescope

jfsestito — Thu, 15 Oct 2020 13:48:17 GMT

I attach with a T2 EOS-M and Meade #62 T adapter into the scope. Using the telescope focuser hasn't gotten images sharp, but in my reading, I have seen I may need to use a diagonal or slide the adapter out a little (tighten with scope's thumb screw) to add a little more length. Cloudy tonight, so will have to wait for next, clear night.

Re: EOS M100 and sharp focus with a telescope

Waddizzle — Thu, 15 Oct 2020 14:55:32 GMT

I would try the EF/EFM mount adapter and a T-Mount for the EF mount to add the distance.

Re: EOS M100 and sharp focus with a telescope

ebiggs1 — Thu, 15 Oct 2020 14:57:13 GMT

The distance from the back of the Celstron and the camera focal plane is critical. It has to be correct or you will not be able to achieve focus (infinity). There are adapters that are designed to position your camera's image plane at the optimal distance. The focus adjustment built into the lens may not be sufficient if that measurement is not correct as you have seen.

Re: EOS M100 and sharp focus with a telescope

jfsestito — Thu, 15 Oct 2020 15:41:15 GMT

Interesting. Here is current setup to attach camera to scope. I see that Meade also has a variable length adapter, which I just ordered from Amazon ($30 and free returns if not useful).

Re: EOS M100 and sharp focus with a telescope

ebiggs1 — Thu, 15 Oct 2020 16:05:00 GMT

That will probably work (long or short enough) you need to get the length correct.