View Full Version here: : How to lift the Veil?
Camelopardalis
07-08-2014, 09:44 PM
Folks, so I gathered some data on the Veil at Astro Fest, 90 minutes worth, and it's really really faint :help: some nice colours and detail coming through (in the bigger versions!), but the central portions especially are really faint. One interesting thing is the red hue across the whole mid-section of the image, while the left and right edges are much more black, so I'm guessing this is the much much fainter overall nebulous bubble.
I've been trying to be careful with the curves tool to try to lift the nebulosity over the "noise" of the starfield but it also comes at the expense of highlighting some of the similarly coloured stars.
Any ideas as to how I can enhance it further? Is it just a case of more extended subs or more subs, or do I need gather some OIII data and throw that into the mix?
Oh, and as with my other images making the onslaught, this is the ZS71+EQ6+1100D, 23x 4 minute subs (+darks+bias).
As always, any suggestions and experiments welcomed :D
cometcatcher
07-08-2014, 10:04 PM
Nice shot Dunk!
Probably does need more data but I think more could be squeezed out of what you already have as well.
Another on my "to do list" now that I have cleared some northern sky.
Camelopardalis
07-08-2014, 10:43 PM
Thanks Kevin! It's really a lovely object, although easier to see visually to some extent, just not as much detail :D
cometcatcher
07-08-2014, 11:50 PM
Would you have a RAW unmodified TIFF straight out of DSS I could have a play with Dunk? I'm seeing a lot of potential in the data.
RickS
08-08-2014, 07:39 AM
Dunk,
I'm afraid that reddish area looks more like a gradient or uncorrected vignetting in the red channel. It doesn't correspond well to what I've seen in deep images of the Veil.
Good luck pulling some more detail out of the data. I'm sure there's more there if you go digging for it.
Cheers,
Rick.
Camelopardalis
08-08-2014, 08:41 AM
Thanks Rick, so now must be a good time to learn about flats :D
RickS
08-08-2014, 09:21 AM
It's always a good time to learn about flats, Dunk :D You need everything working as well as possible for a difficult northern target like that.
Camelopardalis
08-08-2014, 12:37 PM
:D so I'm guessing flats from a brisk Sydney winter afternoon aren't ideal? :confused2:
RickS
08-08-2014, 12:57 PM
Taking flats some time after the lights is never ideal but they may still be helpful. In a perfect world you'd take the flats before making any changes to the optical train.
Mosc_007
08-08-2014, 03:36 PM
One thing you didn't mention is weather your 1100D is modified or not. If this Nebula is mostly Ha then a stock camera wont pick it up much at all. The Ha is filtered out of the stock camera.
Charles
Camelopardalis
08-08-2014, 03:47 PM
Noted... and now I understand why :help: I just took some flats with a double thickness t-shirt and I must have had the dew shield on wonky :lol: Is there anything to be gained by taking the flats without the (flimsy) dew shield on? Or does that change the light rays too much?
Anyhow, here's another go...it's better...I think...took less curve stretching to bring out the nebulosity.
Camelopardalis
08-08-2014, 03:49 PM
The 1100D is stock, unmoved. According to Wikipedia (FWIW), it's a OIII emitter, so I'm thinking next time around I'll stick the filter on and see what happens.
RickS
08-08-2014, 03:56 PM
Generally it's safest to leave everything the same as it was when you did the lights although taking the dew shield off should be OK unless it was causing vignetting (it would be a very poor design if it was...) Making good flats can be a bit of a challenge.
Camelopardalis
08-08-2014, 04:05 PM
Thanks Rick - the evil dew shield is just a small foam mat I rolled up and gaffer taped together at astrofest, after discovering dew on the objective on the first night just using the WO shield. I stuck it on this afternoon to replicate, as closely as possible in daylight, the original conditions.
I might give it another go without foam mat tomorrow then, although I'd prefer to focus on something astro proper at night instead of a distant cloud :D
Btw, in the above image I noticed fuzzy rings appearing around the bright stars too. I don't see the effect in the first try, despite all the extra curve stretching involved :confused2:
cometcatcher
08-08-2014, 07:25 PM
The repo looks much better Dunk. :thumbsup:
LewisM
08-08-2014, 08:15 PM
Best I can do with the supplied JPEG
Camelopardalis
08-08-2014, 08:23 PM
Thanks Kevin!
But WOW! LewisM...amazing...that came out of my ropey JPEG?! :eyepop:
LewisM
08-08-2014, 08:30 PM
It's all there - just stretch each channel rather than the entire image
Camelopardalis
08-08-2014, 08:35 PM
Thanks LewisM - will give it a try!
LewisM
08-08-2014, 08:38 PM
Go here: http://www.atalas.net/
And click on LEARN. Watch Louie's tutorials. Helped me enormously. Plus he's a forum member here too :)
LewisM
08-08-2014, 09:01 PM
Did a mild HDR version too...
Camelopardalis
08-08-2014, 10:38 PM
Great - thanks Lewis!
LewisM
09-08-2014, 09:35 AM
I also de-bloated your stars just a touch too.
Camelopardalis
09-08-2014, 11:53 AM
Thanks Lewis! Yeah they did look like they'd been drinking the blue juice :D
Camelopardalis
10-08-2014, 03:17 PM
I still need to figure out how to tone down and debloat the stars, but I think it's starting to look a little better... still not great, and I'm learning the errors in my imaging ways :lol: but also some neat processing stuff :)
raymo
10-08-2014, 03:37 PM
Hi Dunk, Page 88 of the S & T mag for Aug/Sept will show you
how to manage your star problem.
raymo
Camelopardalis
10-08-2014, 07:52 PM
Great - thanks for the heads-up raymo :thumbsup:
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