Quote:
Originally Posted by Joshua Bunn
Very nice Eric, Some great resolution there under those skies and that scope. Is this a remote setup?
|
Yes, it is accessed over a satellite connection and powered by solar panels with battery bank.
Quote:
Originally Posted by multiweb
Monster scope and great result.  I'm surprised a PME carries that weight. That's about 70kg right? |
That's right, the scope is 140 lbs and the image train comes in easily at over 10 lbs, and I ditched the versaplate, the PW saddle is bolted straight onto the PME dec head, making the scope another inch closer to the RA balance point, even so I'm really at the PME's limit. In fact the tracking is iffy enough that I am upgrading the mount in the very near future.
Quote:
Originally Posted by gregbradley
Planewave did bring out a set of baffles you can install on the corrector. I installed them on mine. Reflections arcs, streams of light from bright out of frame stars are definitely the weaknesses of the CDK scope. Mine has improved somewhat but I did get an annoying arc in some otherwise lovely galaxy subs recently.
...
I have also read that the carbon fibre struts can reflect and reports covering them with flock can help (at the expense of the occasional dropped fibre on the mirror.
I suspect the scope's performance could be improved by flocking the inside of the tubes, the struts,installing the baffles if its an earlier model and making sure you have the latest secondary shroud.
|
I was a bit suspicious that the baffles would fully clean up the arcs after my experiments, but I'm very happy with the flocking, it wasn't that hard to do (Mark and I performed the operation on site at night). And yes I did put flocking on the carbon fiber trusses too, since I had caught the odd weird reflection off them (which looked different than the lens cell artifacts). Otherwise the inside of the scope was dark enough and the secondary baffle was only a problem on the 17" AFAIK. Now when I point right next to <1st mag star I can't even tell it's there!
Some have noted the somewhat noisy appearance and decon artifacts in the image. Yes I have struggled with them too, one day they distract me the next not so much. A few comments though:
1) When smoothing the background and very low light features, very often the small faint galaxies get wiped out or smudged very badly at the least. (See the very remote "fish" galaxy bottom middle, and the interacting pair just to the left of Arp244 where one spiral is strung out into a j shape)
So I tend to go very easy on this at the expense of noise. I'd rather attack with more data (which works under Ark's dark skies)...and I agree this image could have used easily another 3-6 hours of luminance. But as the frames were coming down and the artifacts were piling up I was getting a bit frustrated and was going to can the whole series.
2) Gibb's rings (decon artifact): I wish I could control these better, they are often the limited factor to how much one can sharpen. I knew I was on the edge for this one, especially at 100% zoom. But they don't show on a print and the tiny brown dust lanes come out so well with decon...ah well next time.
Note I only used MaxIm for processing (and CCDSharp for LR decon), no selective masks or photoshop tools, which limits me in the kind of adjustments I can do, but I'm ok with that.
3) Flats were not that great. They showed a ying/yang pattern when flipping east-west, and were not always repeatable. A real bear when trying to tease out faint details (see the magenta blotch near the streamer intersection), in fact some good friends of mine remarked long ago that the ultimate "depth" limit of an image was usually the flat quality. The S&T deep field challenge years back was won because of better flats. Never skimp on flats!
During the flocking trip I also adjusted the centering of the secondary mirror, flats are now better, but not perfect. If I make the flats perfectly symmetric the spider vanes are slightly askew and I get wider diffraction spikes...so compromise again.
Does anybody think the image is too blue? I was sorta prepared for an onslaught of: it's way too blue!!!
Thanks all for the comments.
Best Wishes,
EB