[Mark]

A little experiment I did tonight to find the actual limiting magnitude of the 40D's Live View. Using my 8" SCT @ f/6.3, I started with a mag 2 star and went in (roughly) half mag steps down to where I could not see the star in the main live view window.

I found approx mag 5.5 to be the limit in the main window. Using the zoom mode I was able to see better than mag 6 but that is where I stopped.

I then slewed to a mag 4 globular cluster but I was unable to see the object in either normal or zoom mode in the live view. I can only conclude that low surface brightness objects are going to problematic with respect to using live view for focusing.

Therefore unless there is a mag 5 to 6 (approx) or brighter star associated with a DSO, live view will not help me focus.

I would like to here form other 40D users with different types of scopes (newts or refractors) to see what results you are getting.

I would also be interested in whether anybody has had any success with a parfocal eyepiece setup for their dslr?

Cheers,
Mark