Imaging Train

We are new to astrophotography.

We have a Meade 16" and are using a modified Canon DSLR Camera. We are in a situation where we need to use an altitude azimuth setup. We would like to take some 15 minute pictures and have purchased a Meade field de-rotater.

Once we get the field de-rotater, the micro focuser, a 6.3 reducer, an off axis guider and a T-mount in front of the camera, we have quite a long setup.

Here's my questions:
How far can the camera be back away from the telescope?

How far from the focal reducer does the camera neet to be positioned?

If the camera is to far away do we loose resolution - light etc?

There are probably other questions that I need to ask. Can someone help us?

Richard Rives

Richard,
Wow, lots of questions...

Distance detween the camera and the focal reducer is critical - it determines the focal reduction. To get the ideal .63 reduction, you need about 85 mm. Focal reduction trades of resolution for a larger field. So, yes,putting the camera further away from the reducer looses resolution.

If the camera / focal reducer combo is too far away from the backplate, Then you can't reach focus. You will know - you focus the stars smaller and smaller and then hit the end of focus travel before you reach focus. I don't see this happening with your SCT though with a 0.63x reducer.

The only light you *lose* is