[avandonk]

Thanks all. I just wanted to show what you can do with an $800 achromat and a nebula filter. Note this achromat is an F4.5 with the FR/FF. That is why there is so much nebulousity. I will collect a HDR data set with the 100ED and 'colour in' all the stars.

If I can get an unvignetted (is that a word?) 150mm diameter F5 achromat to have the same quality stars at the corners as at the center with a full frame. Imagine what you could all do with a C size sensor. You would only need a resonable FR/FF and a nebula or UHC filter.

The other Skywatcher in this size is a 150mm diameter F8 and that would be even better if you wanted tighter stars although you lose the abilty to collect as faint nebulousity.

At a slightly smaller scale you could use an 80ED to collect full spectrum data and say a 120mm achro for the nebula data. Just a thought.

Bert