NGC 253 processed as a dim dwarf galaxy

[sjastro]

With all the great NGC 253 images exhibited recently I decided to revisit my own image and reprocess it.

Reading about the halo around NGC 253 gave me the idea of processing the bright NGC 253 as a faint dwarf galaxy in order to bring out the halo.



Ref:- http://arxiv.org/abs/1401.1665

The processing is the same as discussed in the Carina Dwarf galaxy thread.
90 min luminance image BRC-250, ST-X10ME.

Higher resolution here.
http://members.iinet.net.au/~sjastro/Ngc253_halo.jpg

Clear skies

Steven

[RickS]

An interesting experiment, Steven.

In fairly deep data (in particular, an image by Mike Sidonio and one of mine) I have seen an obvious lobe of halo to the South that extends as far as TYC6421-01351-1. Perhaps you need more data to pick that up?

Cheers,
Rick.

[Placidus]

Hi, Steven,

This is really good juicy stuff. I like the science and what you are attempting. The article seems to show that there is no outer "edge", just as the sun's 'atmosphere' effectively extends to Pluto and beyond, just getting thinner and thinner. So the job becomes showing that at some given distance, the image is statistically significantly brighter than the background. That means getting a really good image of the background.

That in turn means a really cold chip, really good flats (that's where I fall down!), and an incredibly dark sky, so no thin cirrus, no moon, and photographing high above the horizon out of the mirk and skyglow.

Avoiding these sources of artifact might be even more important than long subs and a deep stack.

Good project and well worth doing.

Best,
Mike

[sjastro]

What a brain snap using a developmental algorithm.:shrug:

Here is the correct version.
http://members.iinet.net.au/~sjastro/Ngc253_halo.jpg

Clear skies

Steven

[atalas]

Good work Steve....both image links look the same to me so I guess you updated the first one.

[sjastro]

Thanks Mike.
Since I prefer to image the more obscure and fainter object, the background plays a very important role in processing for me.





Thanks Rick.
I had a look at your fine image.
Then it dawned on me I had used the wrong process, a legacy I suppose of processing an image a 4.00am.:rolleyes:

The new image is up.

Regards

Steven

[RickS]

Now that's a *halo*, Steven! :thumbsup:

[Andy01]

very, very cool and a great 3D rendering - now can you add colour to that?

[sjastro]

Thanks Rick.
It looks better but can still be improved on.



Thanks Andy.
I do have colour.
Once I'm satisfied with the luminance I'll add the colour.

Clear skies

Steven

[sjastro]

Thanks Louie.

I've updated the first image in the link you can see the differences in the attachments.
Frankly the first attachment is a bit of an embarrassment.:shrug:

Regards

Steven

[sjastro]

I have performed a slight sharpening of the image and included an extra iteration of the algorithm to bring out further detail in the halo.

http://members.iinet.net.au/~sjastro/Ngc253_halo.jpg

Regards

Steven

[Rex]

Very cool stuff Steven, watching and waiting to see the full colour version.