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Resolution/detail
A paltry 30 minutes (6x 5 minute subs) of Eta Carina. I used a f5 8" Newtonian on an HEQ5 Pro, with a Prostar Guide LP-Mono camera as a finderguider, and imaged using a modded Canon 40D DSLR with a Baader CLS-CDD clip filter and a f5 Coma Corrector. Was a first with this combo so quite pleased in the end. Got my mirror far enough down the tube to bring it all to focus and can still (just!) collimate the primary. Had no real issues guiding (no wind) although balancing the setup required three 5kg counterweights spread across the bar. Astrotortilla refused to work but it was still easy enough to track down the Nebula. Processing was quick and nasty using Nebulosity 4 (subtracted darks and bias removed flats, normalized, debayered, stacked, auto colour corrected, stretched etc.) and then a bit of fun with the iPhone and iPhoto. Processing is probably my next area to really explore with a degree of seriousness.
I certainly got more detail this time than I've got previously with the ED80, and wonder what the key factors in getting more resolution and detail might be. A 5 minute exposure on the 8" Newt with the CLS filter certainly filled the histogram to a tad beyond the halfway point so wonder firstly if a longer exposure with the ED80 (at f6.4), that yielded the same 'fullness' of the histogram, would get me a similar result? Or would just more stacked subs add up to the same thing?
The image scale with the 8" Newt is also narrower. I'm assuming this helps get more detail too or is this not true with photography? I have an ED100 coming my way with a similar field of view. If the scale was the same and I exposed for longer, or stacked more subs, (it'd be an f7.5 or so) would this yield the same resolution?
How much longer would I need to expose on the ED100 at f7.5 to match the f5 8" Newt? Or how many more subs would I need?
Given there are going to be windy nights the 8" Newt is not always going to be viable on the HEQ5 Pro. Is my best option in this case slightly longer, or more, exposures on the ed80 or even longer, or more, exposures on the ED100?
Sorry for the long post and all the questions :-/
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