Sculptor Galaxy from dark skies

[andyc (Andy)]

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

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 , 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

Larger version of the closeup.

Larger version of the wider view.

[dylan_odonnell (Dylan)]

Turned out fantastic! Good job!

[Placidus (Mike and Trish)]

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 (Michael)]

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 (Rick)]

Details and star shapes are quite good, Andy.

[Paul Haese]

Originally Posted by strongmanmike

I see not reading posts properly is alive and well

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 (Michael)]

Originally Posted by 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.

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 (Lee)]

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

[andyc (Andy)]

Originally Posted by 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.

Originally Posted by 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

Originally Posted by 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.

Originally Posted by 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

Now now guys, no fisticuffs at dawn I don't want to be responsible for the falling-out of two of the best photographers on this forum . 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 (Rick)]

Originally Posted by andyc

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.

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 (Andy)]

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, as well as attached an updated version below.

[RickS (Rick)]

That's quite an improvement, Andy.