NGC 253 Silver Coin galaxy

[telecasterguru (Frank)]

Very nice image indeed.

Frank

[strongmanmike (Michael)]

Yes, this is a nice result on NGC 253 Steve, very good work indeed

Mike

[TrevorW]

Nice work Steve,

maybe a tad of sharpening and push saturation a bit more but just my opinion

[iceman (Mike)]

Lovely image Stephen!

[RickS (Rick)]

Very nice, Steven!

[Stevec35 (Steve)]

Definitely more than run off the mill. Very nice natural looking NGC 253.

Cheers

Steve

[sjastro]

Thanks to all concerned for the comments.

Clear skies

Steven

[Ross G]

A beautiful galaxy photo Steven.

Great detail and colour.

Ross.

[sjastro]

Thanks Ross.

Clear skies

Steven

[madbadgalaxyman (Robert)]

Originally Posted by sjastro

Hello Robert,
I suppose the HII regions are small compared to the size of the galaxy. M31 springs to mind as well. At the other end of the scale is NGC604 in M33.
Steven

Hi Steven,

The visual (blue wavelengths)(optical) Hubble type assignment of
NGC 253 is Sc, or , just possibly, it manifests as a very weakly-barred Sc galaxy.

However, a heavy dust screen and an unhelpful orientation tends to falsify the true morphology of this galaxy. The so called highly-foreshortened "bar" which is observed in visual or blue wavelengths is not actually the real bar structure within this galaxy; it is a "pseudo bar" that is merely composed of the light that is left over after the heavy dust clouds block the rest.

In near-infrared regime, the overall structure of NGC 253 is very clear; it is strongly barred (a long and narrow bar), and there is, in the literature, an extant (from Near-infrared images) morphological Hubble type assignment of SBb
(in other words, it is a barred Sb galaxy).

The Hubble Class of SBb is highly consistent with the small HII regions.

cheers, Robert

(Much of the star forming activity (young stars, HII regions, etc.) in this galaxy occurs very near to its centre, but this region is highly obscured by dust at visual wavelengths)

P.S. Just had a look at your image of the Grus trio; good work! The structure of all three galaxies is very clearly seen in your image; unlike in many other amateur shots.

[sjastro]

Originally Posted by madbadgalaxyman

Hi Steven,

The visual (blue wavelengths)(optical) Hubble type assignment of
NGC 253 is Sc, or , just possibly, it manifests as a very weakly-barred Sc galaxy.

However, a heavy dust screen and an unhelpful orientation tends to falsify the true morphology of this galaxy. The so called highly-foreshortened "bar" which is observed in visual or blue wavelengths is not actually the real bar structure within this galaxy; it is a "pseudo bar" that is merely composed of the light that is left over after the heavy dust clouds block the rest.

In near-infrared regime, the overall structure of NGC 253 is very clear; it is strongly barred (a long and narrow bar), and there is, in the literature, an extant (from Near-infrared images) morphological Hubble type assignment of SBb
(in other words, it is a barred Sb galaxy).

The Hubble Class of SBb is highly consistent with the small HII regions.

cheers, Robert

(Much of the star forming activity (young stars, HII regions, etc.) in this galaxy occurs very near to its centre, but this region is highly obscured by dust at visual wavelengths)

P.S. Just had a look at your image of the Grus trio; good work! The structure of all three galaxies is very clearly seen in your image; unlike in many other amateur shots.

Thanks for the information Robert.
Next season I'll try imaging NGC 253 in NIR for the barred structure.

Regards

Steven

[stardust steve (Steve)]

Wow nice image. Love how you processed the star forming regions

[madbadgalaxyman (Robert)]

Originally Posted by sjastro

Thanks for the information Robert.
Next season I'll try imaging NGC 253 in NIR for the barred structure.

Steven

Good idea! It will be interesting to see if the bar can be be seen at NIR wavelengths that are accessible to amateurs. In the optical regime, there is, at best, a suggestion of a bar; so perhaps you will have at least some success "digging it out" from all the obscuring dust clouds.

Perhaps you can also start to pick up some of the intense light from the violent star formation occurring in the central regions of this galaxy??! (totally invisible at 600nm)

I would suggest that, whatever you do (or do not) uncover in your NIR image of NGC 253, the overall structure of this galaxy will at least be clearer in an NIR image.

The central starburst and the bar are clearly seen in this image from WISE, which is at about 4 microns:


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Another galaxy in which the optical-regime morphology is greatly falsified by a dusty patchy semi-chaotic screen of obscuring material is NGC 2903; it is really tough to see the outline of the bar clearly in NGC 2903, despite a more favourable orientation than NGC 253.
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[iceman (Mike)]

This beautiful shot of NGC253 is now IOTW.

[sjastro]

Originally Posted by iceman

This beautiful shot of NGC253 is now IOTW.

Thanks for the IOTW Mike.

Much appreciated.

Steven

[lhansen (Lars)]

Originally Posted by sjastro

Another run of the mill NGC 253 image.
90m L, 50m R, 50m G, 50 m B ST-X10ME. BRC-250 scope.

High resolution here http://members.iinet.net.au/~sjastro/ngc253latest.html

Clear skies

Steven

Yeah right, if you were imaging with the Hubble maybe

Congrats on a great job

[sjastro]

Originally Posted by lhansen

Yeah right, if you were imaging with the Hubble maybe

Congrats on a great job

Thanks Lars.

I suppose it ultimately depends on how self critical you are.
On many occasions (like with this image) I am rarely satisfied with the final product and and think I could have done better with the acquisition of data and processing of the image.

Regards

Steven

[rogerg (Roger)]

Nice colour, great shot

[sjastro]

Thanks Roger.

And a Merry Christmas to all.

Steven