How can I tell if the spacing is incorrect?

[swag72]

Just received my Baader SCT/2" adaptor for my Equinox 66 (Thanks FLO!). Now I need something else to connect the filter wheel to the Baader 2" - So can anyone suggest what I need there?

Also, when the spacing is incorrect is it simply a case of just not being able to reach focus? For example, when using my DSLR without an extension tube, it becomes very obviously, very quickly that there's just not enough travel to achieve focus. Is it the same as this for a CCD? Or is it not that simple?

[ollypenrice]

To the best of my imperfect knowledge you only need to worry about chip distance from a 'good stars across the image' point of view if there is a flattener/reducer in the system. If there isn't, then you just have to get the focal distance right. Different flattener/reducers have different optimal distances. It would be a bit of obvious good sense if this distance were marked on the reducer, but it isn't on any I've seen!

Olly

[martin_h]

It would be a bit of obvious good sense if this distance were marked on the reducer, but it isn't on any I've seen!

Olly

Now that would be to easy..and where's the fun in that?