IC5146, the Cocoon Nebula taken at Rother_Valley 15 Sept 2012

[The Thing]

HEQ5 Pro (recently re-greased), EQMOD, CdC, LX90 8" UHTC Baader Alan Gee II Telecompressor, Canon 350Da, NO Astronomik CLS-CCD clip filter, Lakeside ASCOM Focuser, Meade 8x50 FinderGuidescope & QHY5, PHD Guiding, APT Astro Photography Tool.

Processed in IRIS. 20 flats, 8 darks, 10 offset/bias frames. 32 x 300s (2h40m) at iso800. Stacked with sigma 1.5 with 1 iterations. Colour and dynamic stretching, no wavelet sharpening this time and binning twicex2.

Full size

[MarkS]

I like that!  You're just beginning to see the dust.  If you can deal with the background gradient I think the dust would come out even better.  Then increase the blue a bit.

What do you mean when you say "binning twicex2"  ?

[MarkS]

Hope you don't mind but I took a liberty of having a go myself 'cos I just couldn't resist:



I think you've got a superb result there!  

Larger version:
http://www.markshelley.co.uk/webdisk/dunc_cocoon.jpg

I removed the gradient as follows in IRIS:
1) Type the command "pointon"
2) Click 10 points on the background near each corner of the image - 40 points in total.  This often works better if you blur the image first (but I didn't in this particular case)
3) Type "poly 1" which creates linear background gradient when followed by the "synthe" command
4) Save this background gradient:  "save my_back_gradient"
5) Load the image again, subtract the background gradient image: "sub my_back_gradient 0"
6) Type the command "pointoff" to stop the annoying crosses appearing each time you click the mouse
7) Adjust blackness of background and enhance colour balance.

[Jim]

Remember you doing this one Duncan. Amazing detail you've captured.

[Carole]

There's some really good data there and you've captured some good star colour as well.

Carole

[JonH]

This is some really good stuff!
Think I need to learn how to use Iris!

[The Thing]

Thanks for the iris help Mark. I had only tried Sunday subsky (blooming smellpeckers!) and various polynomials.
Thanks for you kind comments everyone.

[JohnP]

Well that's a mighty fine Cocoon. Really nice & like your tweak Mark - John

[Fay]

Well done Duncan, very nice Cocoon & great stars!!!!

[The Thing]

Hi all and thanks.

I have followed Mark's instructions for gradient removal in IRIS and uploaded the images to the web, replacing the previous versions. Thanks again Mark, you learn something new every day!

[RobertM]

That looks really excellent Duncan and lovely star colours too.

Robert