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Jeff,
One other thing that impresses me with your shot - the size of the core (how do you do that?).
Why is it the core of M20 is much bigger on your shot than mine? I can easily understand your shot being much sharper and having better colour (a TAK super apo -> S-BIG should beat a SCT -> DSLR hands down) - so that doesn't surprise me. But your image scale does and I am trying to understand why.
The TSA102s is I think an F8, 816 mm focal length tube. My SCT has a focal reducer in the off axis guider bringing my focal ratio down to imaging at 1,500 mm.
Your S-BIG has a 7.4 * 7.4 micron pixel size and close to 2 million pixels. The Canon 400D is a 10MP 5.7µm vs 6.4µm (3888 x 2592 pixel) chip
(so not wildly smaller pixels, but given my sky quality I might be better with 2*2 binning?
But what simple factor makes the core of M20 bigger in your shot than mine - have you a lens in the imaging training or what simple thing have I overlooked?
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