Dusty Spiral Galaxy NGC4945

[gregbradley]

I took this about a month ago.

An interesting spiral galaxy in the Centaurus Group. If you look at the large size you can see dust plumes rising vertically around the centre and along the bulk of the galaxy.

http://www.pbase.com/gregbradley/image/167804961/large regular size

http://www.pbase.com/gregbradley/image/167804961/original large image

CDK17 and FLI ML16.

Greg.

[Stevec35]

The star shapes look to be very slightly off Greg but it's still a good NGC 4945. Not the Sculptor group though but the Centaurus A/M83 group.

Steve

[strongmanmike]

Yeah love those dusty filaments/plumes too and the colour is quite good. Perhaps the star shapes, a slight registration issue and what looks like erosion or minimum filter honeycomb artefacts in the body of the galaxy are working together to let it down a bit when viewed at the full size..? Otherwise, not too bad a shot of this great dusty galaxy Greg :thumbsup:

Mike

[Slawomir]

A very nice image Greg, shows the advantage of a large aperture when chasing finer details :thumbsup:

[Placidus]

One of our favourites and you've done it proud.

We especially like the dusty threads running through the outer part of the galaxy.

Perhaps the centre is just slightly over-sharpened. It does produce a beautiful 3D effect.

The distant barred spiral half way toward top right of the main galaxy has come out very nicely.

[gregbradley]

Thanks Steve. I should really look those groupings up before I say them! Yes there was some tilt that got into the system. Can happen when removing and reinstalling the camera a lot. I did some correction but the stars are not the finest.



Yes there has been one step that did some damage. Fixed now, its more natural.



Thanks Suavi. Yes aperture in the end wins even if it is heavy and expensive!



Thanks MnT. These CDKs collect a lot of light that is for sure. Glad to hear the drought isn't impinging on you too much.

Greg.

[RickS]

Latest version looks great, Greg!

[gregbradley]

Thanks Rick. Little things at the time of acquisition can catch up with you later and cause problems!

Greg.

[atalas]

Love this galaxy Greg!the detail looks fantastic:thumbsup:colour,looks a bit yellowish to me.

[strongmanmike]

Yep, the reworked galaxy looks much better and the sky/background looks great too...except...the stars look to have a residual border, perhaps from a star mask? around them..?..fix that and it will be a bloody ripper :thumbsup:

Mike

[Atmos]

Nice galaxy Greg! Very dusty region but the small galaxies smattered throughout the background a good :thumbsup:

The stars almost look like a collimation issue or a pinched mirror. Could just be the processing though.

[gregbradley]

Thanks Louie. Yes I thought as well at one stage of processing but it seems to be quite strong in yellow around the core like our galaxy is. I could pull that back a bit though.



No not sure what caused that but I tried a few times to correct it. Its evasive but I should be able to track it down. Funnily other data from another object taken same period shows perfect stars.



I think it was tilt from a packer doubling up. Its unlikely collimation or pinched mirror as other data is spot on.
The only change may be the mounting of the camera.Perhaps it wasn't square on its adapter.

In fact come to think of it I took the camera off and cleaned all the filters the next day so it must not have been squarely mounted on the first night. Pinched on the dovetail fitting it attaches with probably was the issue.

Greg.

[topheart]

What a great galaxy!!
Cheers,
Tim

[gregbradley]

Thanks Tim.

I think I will repro this one and see if I can get the stars better. The galaxy part is fine but the stars are a little off. I didn't notice that at the time of capture though.

Greg.

[gregbradley]

OK I fixed the stars up.

Looks like it was some deconvolution on the luminance that shrank the bright cores of the stars but left an outer halo.

I now am happy with the image and like the detail the CDK picked up.

Now an official member of the Royal Society for the abolition of Lucy Richardson Deconvolution! (Mike is the President).

Also toned down the yellowish bias.

http://www.pbase.com/gregbradley/image/167804961/large

http://www.pbase.com/gregbradley/image/167804961/original

Greg.

[RickS]

The antideconvolutionists :lol:

Looks great, Greg.

Cheers,
Rick.

[gregbradley]

Hehe thanks Rick.
;)

Greg.

[strongmanmike]

He he he

[gregbradley]

:rofl: