ngc3621

[NOMH (John)]

Great capture Ray. I like the galaxy the way it is but some of the larger stars look a little funky. Great field of view and the background galaxy is a bonus.

JB

[Shiraz (Ray)]

Originally Posted by Leonardo70

Great image Ray.

All the best,
Leo

Thank you Leo.

Originally Posted by marc4darkskies

Lovely image Ray! Balance looks fine to me. I'd boost the colour a little bit though.

Cheers, Marcus

thanks Marcus - am working on it

Originally Posted by Asterix2020

Nice image Ray. I agree a little more saturation would be good, but I like colourful pics .

Thanks Paul. seems to be majorityagreement that it needs more colour

Originally Posted by Paul Haese

I like the detail in the inner arms, but think like some that the colour could be boosted a little. You might need to manage the bright orange stars when doing the boost though.

This is a good field of view and I think well composed when combined with the field of view it really works. I like the way the galaxy almost fills the field of view.

If it were me I would get some more hours of data. The background has a bit of a salt and pepper look which could be managed by some extra time. Just my opinion but I think getting more data is better than doing noise control.

A galaxy I have not seen much and something I should put on my imaging list.

Thanks Paul. I intend to try for a lot more data, but getting the noise down will be hard on such dim features'

Originally Posted by alpal

Hi Paul,
It's in a great spot at about 1am - almost directly overhead.
The time is now - to image this one.
I hope others do too - it's a great target.

cheers
Allan

Yep Allan - it's right alongside the moon (or at least that's where it seem to spend much of its time).

Originally Posted by NOMH

Great capture Ray. I like the galaxy the way it is but some of the larger stars look a little funky. Great field of view and the background galaxy is a bonus.

JB

Thanks John. Not sure what you mean by funky - if you mean the X shape diffraction pattern, that is due to the six mirror supports and is what this scope does.

regards Ray

[alpal]

Yep Allan - it's right alongside the moon (or at least that's where it seem to spend much of its time).

No - according to Stellarium it's almost directly over head at 1am.

Actually 78 degrees at 1.15 am

[NOMH (John)]

Originally Posted by Shiraz

Thanks John. Not sure what you mean by funky - if you mean the X shape diffraction pattern, that is due to the six mirror supports and is what this scope does.

regards Ray

Hi Ray, not the spikes as my RC does that also. I was talking about the larger stars appear that the cores are really saturated, maybe over sharpened? The smaller stars look great.

JB

[multiweb (Marc)]

A real nice close up Ray. Incredible details.

[Shiraz (Ray)]

Originally Posted by NOMH

Hi Ray, not the spikes as my RC does that also. I was talking about the larger stars appear that the cores are really saturated, maybe over sharpened? The smaller stars look great.

JB

thanks John - yep you are right, something went wrong with those stars - will redo to fix

Originally Posted by multiweb

A real nice close up Ray. Incredible details.

thanks very much Marc.


Repro is progressing, but taking time. regards Ray

[tilbrook@rbe.ne (Justin Tilbrook)]

Nice to your images again Ray!

Great detail as usual, if you don't mind me saying it could a little more saturation.
Don't know what the skies are like your way?
Plenty of clear nights here but the seeing is terrible.

Cheers,

Justin.

[madbadgalaxyman (Robert)]

Originally Posted by gregbradley

A remarkable image Ray. I don't recall see any version of this galaxy before that has captured those outer arms so well.

G'day, Ray,
I totally agree with Greg that the outer extensions of the very faint outer arms are better seen in your image than is usual, even on deep exposures.

Even so, the faint disk of this galaxy is known extend out even further than it does in your image......
a real challenge for astro-imagers

Some of the the outer spiral arms are bent well out of the plane of this galaxy; this bending from the principal plane of the galaxy (as defined by its bright inner disk) is most evident in the single prominent arm on the bottom right of your galaxy image, which gradually bends 90 degrees, but not in the same way that an arm would bend if it was in the same plane as the inner disk region.

Here is an image of the HI disk of this galaxy, taken with a radiotelescope, observing the 21 cm line that comes from neutral atomic hydrogen.
This "image" of the cold neutral atomic hydrogen gas in this galaxy actually represents, using greyscale,
the amount of atomic hydrogen gas in each line-of-sight::

(from the THINGS survey, Walter et al., 2008)

As you can see, the Hydrogen disk, far from being planar, is very bent and warped! In fact, this is one of the weirdest gas distributions known in galaxies that appear mildly perturbed.

The departure of some of the outer arms from the plane occupied by the bright inner disk, is also very obvious in the UV image from GALEX.

cheers,
Robert

This is quite a fiendish galaxy, in its way. At first glance, it looks like just a standard pretty spiral, but the more you look at it, the more the distribution of arms and dust looks anomalous.

[Stevec35 (Steve)]

Nice work on this one Ray. I agree with others that the colour could perhaps be boosted a bit but not too much as I think you are pretty close.

Cheers

Steve

[Shiraz (Ray)]

Originally Posted by tilbrook@rbe.ne

Nice to your images again Ray!

Great detail as usual, if you don't mind me saying it could a little more saturation.
Don't know what the skies are like your way?
Plenty of clear nights here but the seeing is terrible.

Cheers,

Justin.

Hi Justin. I don't mind you saying that at all - in fact, thanks for the feedback.
the seeing for this one was about 2.6 arcsec on average, which is not great. Have recently had some better stuff though, but of course only while the moon was up.

Originally Posted by madbadgalaxyman

G'day, Ray,
I totally agree with Greg that the outer extensions of the very faint outer arms are better seen in your image than is usual, even on deep exposures.

Even so, the faint disk of this galaxy is known extend out even further than it does in your image......
a real challenge for astro-imagers

Some of the the outer spiral arms are bent well out of the plane of this galaxy; this bending from the principal plane of the galaxy (as defined by its bright inner disk) is most evident in the single prominent arm on the bottom right of your galaxy image, which gradually bends 90 degrees, but not in the same way that an arm would bend if it was in the same plane as the inner disk region.

Here is an image of the HI disk of this galaxy, taken with a radiotelescope, observing the 21 cm line that comes from neutral atomic hydrogen.
This "image" of the cold neutral atomic hydrogen gas in this galaxy actually represents, using greyscale,
the amount of atomic hydrogen gas in each line-of-sight::
Attachment 179992
(from the THINGS survey, Walter et al., 2008)

As you can see, the Hydrogen disk, far from being planar, is very bent and warped! In fact, this is one of the weirdest gas distributions known in galaxies that appear mildly perturbed.

The departure of some of the outer arms from the plane occupied by the bright inner disk, is also very obvious in the UV image from GALEX.

cheers,
Robert

This is quite a fiendish galaxy, in its way. At first glance, it looks like just a standard pretty spiral, but the more you look at it, the more the distribution of arms and dust looks anomalous.

thanks for the info Robert. I pushed the luminance as far as it would go (attached) and can see some of the additional extent and twisted shape, but my site is not really dark enough to get down deep.

Originally Posted by Stevec35

Nice work on this one Ray. I agree with others that the colour could perhaps be boosted a bit but not too much as I think you are pretty close.

Cheers

Steve

thanks very much Steve. I am finding it hard to get much colour while still digging out the dim outer arms - I don't want to mess too much with the data, but it looks like treating the core and outer regions separately may be the only option.

regards ray

[Shiraz (Ray)]

thanks very much to everyone for advice. I added more data, tidied up the noise, increased the saturation, tidied up the messy stars a bit, reduced the deconvolution and reduced the scale to hide the nasties that accompany more colour and to improve the apparent sharpness.
http://www.astrobin.com/full/169375/0/
appreciate the feedback to date
regards ray

[madbadgalaxyman (Robert)]

Originally Posted by Shiraz

thanks for the info Robert. I pushed the luminance as far as it would go (attached) and can see some of the additional extent and twisted shape, but my site is not really dark enough to get down deep.

Good stuff, Ray, this is just the sort of ultra-faint material that I love to see!

As mentioned in my other recent N3621 post, there is a commonly used name for very-very extended Extremely Faint Disks which are much more prominently seen in the ultraviolet regime :
"XUV" disks
(short for extended ultraviolet)

cheers,Robert

Just to confuse the issue, some galaxies with outer extremely faint and extremely extended Outer disks, are also known in the professional literature as Low Surface Brightness Galaxies !!
(e.g. NGC 289)