ASI224MC optical train for C8

dave s.

I'm looking for advice for setting up the optical train on a Celestron C8 (actually a Nexstar 8SE) with an ASI224MC. I did a very fast test using M42 the other night (not spectacular results, but it was really for a quick working test) and I realized that I need to add a focal reducer. For the test I just used the 1.25" nosepiece in the diagonal. I'm unsure as to what's the best way of incorporating the reducer, getting the flange distance correct, etc. so I'm hoping someone else here has already figured it out. My preference is to take the diagonal out of the path and just run straight to the camera.

Sam@ZWO

the 224 is very small and you usually don't need to consider the distance between sensor and reducer

einari

Well, it depends on the reducer.

If it's the Celestron f/6.3 reducer the optimal distance is 105mm.

The 1.25" 0.5X reducer has nominal 47.5mm distance.

Increasing the distance you get bigger reduction but image quality gets worse but smaller chip cameras (like ASI224) suffer less than bigger sensor cameras.

http://agenaastro.com/antares-1-25-0-5x-focal-reducer.html

dave s.

Thanks for the advice. I spoke with customer support at the site where I bought the camera, and decided on a .5x focal reducer directly screwed into the nosepiece of the camera (I probably won't need a spacer, but it comes with one if I do). When I get a bit of experience at getting reasonable image with this setup I'll probably get the Celestron F6.3 reducer/corrector and an ADC.