Sculptor Galaxy from dark skies

[andyc]

Alright, I've spent waaay too much time prodding this one left, right and centre. The first picture from a perfect two dark nights astrophotography down at Nerriga south of Sydney. But having seen some of the stunning deep work on show here, this feels a bit, well, amateur for this forum :P

15 x 5 minutes, EOS 60D on 150mm Newtonian at ISO800, HEQ5pro & off-axis autoguider. Lovely dark skies that show all my flat issues are due to local streetlights etc in town! I mostly took this as an afterthought following good images of the Helix and NGC300. But seeing the recent staggering Helix and NGC300 images here :eyepop:, thought I'd put this up first.

I've had real issues with colour balance from my rubbish laptop (laptop blue looks brown/yellow/green on a properly-calibrated screen), so if it looks on your screen much other than yellowish in the middle and bluish on the outside, please let me know! And other comments/criticisms/tips other than "more data" will be most welcome :D

Larger version of the closeup (http://www.pbase.com/andycasely/image/161498591).

Larger version of the wider view (http://www.pbase.com/andycasely/image/161498590).

[dylan_odonnell]

Turned out fantastic! Good job!

[Placidus]

You're up and running. You've caught a big fish on a thin line in short order. You can already see some of those galactic fountain streaks.

[Paul Haese]

Looks ok Andy. More data will help. Colour balance is ok but more data will give you a greater ability to balance the colour well.

I did this myself recently with about 14 hours of data; its dropped down the list a bit. You can see it in my gallery and use that for comparison if you like.

[strongmanmike]

I see not reading posts properly is alive and well ;)

Very good result in most respects but as you say the colour balance is probably a bit off, with the image looking a bit blue. My understanding and experience is that it isn't a good idea to process images on a laptop screen, doing so tends to produce results that look very different to how they look on a traditional monitor.

Mike

[RickS]

Details and star shapes are quite good, Andy.

[Paul Haese]

I did read the post. More data is a legitimate comment if the original poster says he is not looking for it. More data will enable the colour to show through better and provide a better way of getting colour balance.

[strongmanmike]

Don't get ya nickers....t'was just funny that you said the only thing Andy said he didn't need to hear, gave me a little chuckle, that's all, as usual all good fun Paul, relax :)

Mike

[codemonkey]

Good work Andy. The colour does look a bit too blue on my mac.

[andyc]

Now now guys, no fisticuffs at dawn :eyepop: I don't want to be responsible for the falling-out of two of the best photographers on this forum :lol:. But seriously, thanks both for taking the time to comment. Paul, your suggestion on an image comparison is a great one - one thing I'd thought of a bit for dealing with my known colour balance issues on the laptop (however I try, the screen doesn't want to calibrate well). The reason I said about comments other than 'more data', was just that it's one thing I really knew the image needed, so my apologies if I didn't clarify that! But I can build on this 75mins, especially if I can sneak in any more dark-sky time this spring.

Mike and Lee, thanks for the comments about colour balance - can't wait to get a decent monitor. Overlaying Paul's image showed the issue clearly - the sky background still had some blue in it, and I think I have a clean solution, at least for galaxies: use the 'background neutralisation' or 'colour calibration' in PI late in the processing. It'll do till I get a decent monitor :), I'll put up a new version at some point. Though I'm not sure how that'll go for nebula regions/rich starfields! All a learning process...

Dylan, Mike & Trish and Rick, thanks for the kind comments!

[RickS]

The BGNeutralization and ColorCalibration processes are designed for use on linear data. I suspect they won't work well once you've started stretching. The best way to get a neutral background is to use BGN and CC early on and don't do anything in later processing to add a cast to the background. Failing this, you can always construct a mask exposing the background, e.g. with RangeSelection, and use CurvesTransformation to desaturate it.

Cheers,
Rick.

[andyc]

I do apologise for resurrecting a slightly old and ordinary thread, but I should thank Rick (and everyone else) for all the advice! I also got around to correcting the colour a little on my image and have updated the PBase image (http://www.pbase.com/andycasely/image/161498591), as well as attached an updated version below.

[RickS]

That's quite an improvement, Andy.