Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Carole on Sep 30, 2014, 19:17:42

Title: M16 Eagle nebula Hubble Palette
Post by: Carole on Sep 30, 2014, 19:17:42
This is my last image from Kelling.

Ha 5 x 1200secs
Oiii 3 x 600secs binned x 2
Sii 3 x 600secs binned x 2
Atik314L, Skywatcher Ed120 and NEQ6
Captured in Artemis, stacked in AA and processed in Registar and Photoshop.

(http://cdn.astrobin.com/images/thumbs/9cbff7eb3423b273e4ba9a2a277df65d.1824x0_q100_watermark.jpg)
Title: Re: M16 Eagle nebula Hubble Palette
Post by: MarkH on Sep 30, 2014, 21:13:33
Fantastic Carole, I wouldn't worry about the colour of background stars if you can get nebulosity colours like that.
Title: Re: M16 Eagle nebula Hubble Palette
Post by: Carole on Sep 30, 2014, 21:47:18
Thank you Mark

Carole
Title: Re: M16 Eagle nebula Hubble Palette
Post by: MarkS on Sep 30, 2014, 22:08:23
I love the Hubble palette on this target. 

However, there does appear to be some colour fringing on the contrasty parts, giving the impression that the layers are not properly aligned.

Mark
Title: Re: M16 Eagle nebula Hubble Palette
Post by: Carole on Sep 30, 2014, 22:20:53
Quotegiving the impression that the layers are not properly aligned.
Yes Registar which is normally the ultimate weapon for doing this, did not align 100% accurately on this image, much of it was fine but there were some small areas where it did not.  I tried it more than once and there was no improvement, I therefore had to resort to some manual manipulation where it was more obvious. 

Carole

Title: Re: M16 Eagle nebula Hubble Palette
Post by: MarkS on Oct 01, 2014, 00:01:44
Thinking about this, if you took it at Kelling then it must have been very low in the sky and so the subs likely contain distortion caused by atmospheric refraction.  Since the distortion is non-linear it can often be impossible to get complete registration right across the frame.  This is probably the problem you are seeing.

Mark
Title: Re: M16 Eagle nebula Hubble Palette
Post by: Carole on Oct 01, 2014, 07:39:31
Thanks for the explanation Mark, it makes sense.

Carole
Title: Re: M16 Eagle nebula Hubble Palette
Post by: MarkS on Oct 01, 2014, 19:25:53
You may find that if you crop the central region of each frame and register them then the central region may come out better.

Mark
Title: Re: M16 Eagle nebula Hubble Palette
Post by: Carole on Oct 01, 2014, 21:21:39
You mean register it in sections and then do a mosaic? 

Yes might give that a try when I have some spare time.

Carole
Title: Re: M16 Eagle nebula Hubble Palette
Post by: MarkS on Oct 02, 2014, 06:10:46
Quote from: Carole
You mean register it in sections and then do a mosaic? 

Yes, but you might get away with just re-doing the central section (where it shows most) and overlaying it onto the original.