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M31, now in colour

James

By James
in Imaging - Deep Sky

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James

James

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With a couple of recent clear nights I've been able to add some colour to my earlier M31 image . I've added in 20x 2 minutes of Red, Green and Blue respectively, thrown it all in a pot and stirred and this has come out :) I live in fear of colour in my images and whilst I'd like a little more blue in the arms I'm not unhappy with how this has turned out. It was processed on an uncalibrated monitor so apologies if it's actually bright pink/turquoise/yellow (delete as appropriate!)

I'm going to give it another tweak I think but sleep first! I understand M31 is heading our way at speed, perhaps I should wait until it's closer for a better image ;)

I've also changed the orientation since I did my luminance. My wife said it's current orientation is better... hmmm..

Taken using a Borg 77EDII, Baader LRGB filters, SX H694 camera. Captured with Nebulosity, processed in PixInsight.

25x 2 min Luminance, 20x 2min each R G & B.

Criticism is more than welcome, I'd like to get more comfortable with colour in my imaging and I always listen to advice!! :)

James

post-649-0-02749900-1378850911_thumb.png

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davew

davew

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Hi James,

I suppose the only way of finding out if your colour is correct would be a G2V calibration. Not something I know too much about. I've read that a body of opinion suggests that the centres of large Galaxies are close enough to use as a measurement. I took your PNG and tried it out. Using M31 centre there was very little colour change. A touch more blue may be. Using M101 the change was a much redder inner area and dust lanes in M31. Not too bad but the blue didn't jump out. Given the data you have then you're not far off and I find it pleasing to my eye.

There are some images that show a bright blue outer ring all the way round and very deep. They may not have been " Enhanced " but they look it to me. There are others that have a fireworks display going on. The middle road is like yours with a hint of blue at either end. Very nicely done.

Dave.

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James

James

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Thank you Dave :) The only way to really boost the blue usually resulted in a blue halo around the galaxy - I couldn't get my masking so precise as to stop that occurring. Personally I like the colour that is there and am happy to stop there :) Note to self... really must get monitor calibration sorted though..

James

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ollypenrice

ollypenrice

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Super job. I admire this a lot.

On colour I think this target tends to default to a slightly greenish monochrome, possibly because the colour differentiation is very low. I've found that, the more data you have, the more it tends towards blueish outer arms and reddish core. I've always yielded to the temptation to exaggerate this trend. I'm not advocating this, just confessing!

One simple objective test is to look at the starfield and its star colours with an HR diagram in front of you. Are your red stars red and your blue stars blue? If not, maybe you have not differentiated the colours sufficiently. (I haven't done this with your excellent image. It is one of the things I do to evaluate my own.)

Olly

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James

James

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When you say added in 20x 2 minutes of Red, Green and Blue respectively, are you saying you image through R.G.and B filters respectively?

Neil.

@Neil, I took 25x 2 minutes with just a luminance filter (Hutech IDAS), then 20x 2 mins through a Baader Red filter, 20x 2mins with a Green then 20x 2 mins with a blue filter (spread out over two nights mind you).

I then used PixInsights LRGB combination tool to put the four resulting images together and processed from there :)

On colour I think this target tends to default to a slightly greenish monochrome, possibly because the colour differentiation is very low. I've found that, the more data you have, the more it tends towards blueish outer arms and reddish core. I've always yielded to the temptation to exaggerate this trend. I'm not advocating this, just confessing!

My image was a green monochrome when I started :) I used PixInsights SCNR tool to remove a little of the green then boosted the red and blue a little and went from there. I think I've pushed the colour as far as I should - some of my stars are showing signs of the colour being pushed a wee bit too far...

One simple objective test is to look at the starfield and its star colours with an HR diagram in front of you. Are your red stars red and your blue stars blue? If not, maybe you have not differentiated the colours sufficiently.

I've checked a few and the colours seem to be correct so far - that must be good :)

Thank you all for the kind comments everyone :)

James

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