Quote:
Originally Posted by jase
Tip of the hat, Dave. Very well executed image. So much on display and to dwell over for lengthy periods of time. The mosaic certainly adds pleasing resolution to what is a well frame subject. No confusing message. You certainly made the most of the clear nights in which by the sound of things provided solid data to work with. The end result at least indicates this. Well done. More please...
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Thanks Jason. Much appreciated, especially considering your imaging experience
We definitely had a lucky run of good weather in Brisbane in August (a pleasant surprise considering the first half of the year). I certainly wasn't originally expecting to be finished before October!
Quote:
Originally Posted by strongmanmike
Wow....pretty incredible to look at Dave 
There is lots to see in there and clearly a lot of work has gone into it 
Now, this is not a criticism and Ivo may hammer me here   ...but to me some of the detail looks like it has been kind of "created" by the processing  in a similar way that the minimum filter can. Don't get me wrong it is certainly a detailed image but looking at some of those thin wisps they look like they were fatter streaks made artificially "thinner" by the software  . So what you might say (and well yes, so what it may be  ) but looking at the spotted background I am not totally convinced that some black magic isn't going on here...at least to some degree Hope you aren't offended by these comments just an observation, it is an amazing deep nebula image
MIke |
Thanks Mike!
No offended at all, if anything I'm actually rather curious... I think I know the types of false-signal artefacts you're referring to; they're particularly infamous amongst the planetary imagers.
To the best of my knowledge, all the structures that I can see in the final result are visible in the raw screen-stretched-only stack (so they're "real" as far as I'm aware).
I've attached two crops with no processing. The first image is of a very high SnR region that has been linearly stretched (0, 0.5, 0.33) in PI, followed by 200% resampling using nearest neighbour for clarity. The second is of a very low SnR region in the background - linearly stretched (0, 0.5, 0.0125) and 200% resampled again. In both cases, there was *no* other processing - no wavelets, no multiscale processing, no sharpening, no deconvolution, etc applied.
When I compare the raw stretches to the final result - I can see the same fine structures in both. The "spotty background" is just noise from the depths of my CCD due to the extreme stretching (20 subs isn't really enough to smooth out the background given the amount of thermal noise I have with 60 min subs @ -10 deg C). At 86 hours, I'm definitely at the "diminishing returns" point of further data collection
I think the "black magic" you refer to comes from PI's amazing ability to compress dynamic range. There's a
huge amount of subtle detail in the Cat's Paw, but I think it tends to get swamped by the dynamic range. I'm very much a PI newbie though so it's sledge hammer strokes rather than fine tooth comb at this stage
Anyway, thanks for your honest opinion. I'm curious what you think (or anyone else) after seeing the unprocessed crops?
Quote:
Originally Posted by astronobob
A Truely remarkable piece of Work Dave  Just shows what Mega Data can do, 100% credit to Ya  |
Thanks Bob! This is pretty much the only astro thing I've been working on since we last caught up in Leyburn... definitely a labour of love