Quote:
Originally Posted by g__day
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?
|
Hey Matthew
OK all the information you have is correct for my telescope and camera ... I dont have anything in the optic train other than the scope, a hollow TAK adapter tube and the camera. Thats it mate ... I do have a TAK Focal Reducer but it wasnt used in that shot and if it was then it would make the whole picture smaller not bigger. So Matthew, I cant answer the question, but thanks again for your input.
Jeff