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M51 Whirlpool Galaxy


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Even though I have taken flats (for L, R, G and B), darks and dark flats, I still get  an 'uneven' background . Also, now I have posted it on here, it looks VERY blue... Not sure where that comes from or what to do about it. I notice I have different numbers of subs for each colour channel, is that a problem ?

1491893889_20200412-M51LRGB11Apr2020.thumb.jpg.4faf109d34571e4063d25a3f33b7126d.jpg

 

Gain 139
Offset 21
Exposures:
Luminance 114s x 55 binned 1 x1
Red 114s x 32 binned 2x2 , Green  114s x 24 binned 2x2  and   Blue  114s x 28 binned 2x2
Calibration frames: Darks, Flats and Dark Flats.
PHD2 Dithering
Equipment: Celestron 9.25 XLT at F10,  Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope
Software: Ascom 6, Eqmod, Cartes du Ciel, AstroPhotography Tool, PHD2, Sharpcap
Processing: DSS to align and stack the subs, PS CS5 to combine and stretch RGB and stretch Luminance and then to create LRGB. Lightroom 6 to develop image further.

 

Edited by stevewanstall
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3 hours ago, geeklee said:

Very nice image Steve. Doesn't look too blue to me, maybe a slight green cast to my eye (being picky)

Great FOV with the 9.25. 

It's a lovely telescope, as nice as everything I have read about it. I would like to get an adaptor for the mount so I can have my SW ED80 for wide field view alongside.

Maybe my monitor isn't helping, re the colour cast. Have to check it for colour trueness maybe.

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3 hours ago, MarkAR said:

Looks fine on my laptop straight on, no blue or green cast.

When I tilt the screen there is a definite purpleness overall.

Putting our views together , it's a bit of a rainbow! Just missing the red end now 😂

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As mentioned, a bit green/yellowish to my eyes too. I don't really see much of the uneven background though. But great data! And I couldn't help myself, having a twiddle with it in photoshop. This is how I personally would color-balance it :)
Using the color balance tool, until the background is nice and black, giving my eyes "rest" and then looking at it again. A curve, boosting the blue areas of the galaxy, and then a slight saturation boost + some local sharpening on the dusty parts.


1491893889_20200412-M51LRGB.png.75a2932a91af8ff35670e386b0d25efb.png

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2 hours ago, The-MathMog said:

As mentioned, a bit green/yellowish to my eyes too. I don't really see much of the uneven background though. But great data! And I couldn't help myself, having a twiddle with it in photoshop. This is how I personally would color-balance it :)
Using the color balance tool, until the background is nice and black, giving my eyes "rest" and then looking at it again. A curve, boosting the blue areas of the galaxy, and then a slight saturation boost + some local sharpening on the dusty parts.


1491893889_20200412-M51LRGB.png.75a2932a91af8ff35670e386b0d25efb.png

Thats a big improvement on what I was able to do> I shall have a play tomorrow and see if I can try and match this. Thanks for the tips.

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