Ngc 4945 in Centaurus.

[Geoff45]

Removed yellow colour cast. (Same links for main image, didn't bother to reload thumbnail)

Dusty galaxy taken during the April new moon period.

http://www.astrobin.com/246326/
Higher res here: http://www.astrobin.com/full/246326/0/

Telescope: 12.5" Plane Wave
Mount: AP900
Camera: FLI proline 16803
Exposure: 3h 50m with LRGB filters. Colour was binned 2 x 2.
Field of View 34' x 34'
Acquisition: Maxim DL
Processing: PixInsight

NGC 4945 is one of many peculiar galaxies that populate Centaurus. This remarkable spiral galaxy is seen almost edge-on, and the spiral structure is chaotic and difficult to discern. In part this is because the galaxy is itself extremely dusty, and is seen through dust in the Milky Way. These effects together account for its yellowish hue. The dust in NGC 4945 absorbs most of the visible light, especially the blue light from the numerous bright stars known to be present within the galaxy. This energy is re-radiated at infrared wavelengths, which penetrate dust more readily, which is why the galaxy is found to be unusually bright in the infrared.


Geoff

[Regulus]

Love the palette you've used for this image Geoff. Gives the galaxy some detail depth, and a nice dusty look :-)

Well done

Trevor

[Shiraz]

Beauty Geoff - good smooth detail. My first thought was that it was lacking in blue, but then, I guess that it should be if it is behind some heavy dust. Nice work.

I have also been trying 2x2 colour binning and can't fault it as a way to speed things up - is that your experience?

[Placidus]

Another very fine image, Geoff.

That big blue star (xi 1 centauri) is spectral class A0, I think. You've captured its colour contrast with the yellow dust-obscured galaxy beautifully.

You've also brought out lots of internal detail and subtlety in the dust lanes.

Nice work.

[Atmos]

Very nicely done! Used to seeing more colour in galaxies but as you say, viewing it through vast amounts of dust can tend to remove colour. The galaxy itself looks like it is nothing more than a very distant giant cloud of dust.
You have also managed to tame that reasonably bright star too!

[Geoff45]

Thanks Trevor


Thanks Ray. Most of the images on the web are similar, although some deep images show tinges of blue and red http://apod.nasa.gov/apod/ap150528.html
Yes, I think colour binning is the way to go unless you have loads of imaging time. I tried bin1 for colour for a while, but I was always having to push really hard to get good saturation.

Thanks Mike and Trish. This was actually quite hard to process, in particular taming xi Cent and pushing the contrast in a fairly bland galaxy.


Thanks Colin

[RickS]

A fine image of this peculiar galaxy, Geoff. The contrasting colours of the galaxy and blue star make a very pretty composition.

Cheers,
Rick.

[strongmanmike]

Nice composition Geoff and while I'm thinking there could be a little more colour in the galaxy, overall a very pleasing looking shot of this unusual galaxy :thumbsup:

Mike

[Ryderscope]

Nice one Geoff. I like the way the subdued colour works out on this one along with the detail in the galaxy.

[Geoff45]

Thanks Mike. Really need to go very deep to get colour in this one, alyhough some do manage.


Thanks muchly Rodney.

[Geoff45]

Just uploaded a new version (Same links). As someone pointed out on one of the Yahoo groups, there was a slight overall yellow cast.
Geoff

[RickS]

Geoff,

You've got a slight blue cast in the background now, but it could just be a colour management problem. The ICC Profile in the image is "DISPLAY_1_D65.icm". You might want to try an ICCProfileTransformation to convert it to a device independent colour space like sRGB or AdobeRGB.

Cheers,
Rick.

[Geoff45]

Thanks Rick. I wasn't aware that Astrobin did colour profiles.
Geoff

[deeplook]

Hello Geoff,

very beautiful image! You show us great detail and also some nice backgruond galaxies. Down to the left, there is one hiding behind a star?

Markus

[Geoff45]

Thanks Markus. Yes, there is a small galaxy near that star.
Geoff

[RickS]

It used to strip colour profiles but this was fixed a few months ago.