Grus Quartet of Galaxies

[gregbradley]

I took this one in between Comet Garrad images over the last few days.

Condition were quite good, better than normal.

A group of Galaxies always is a good target and is very photogenic.

Planewave CDK17 F4.45, FLI Proline 16803, Paramount ME, Vixen 95VMC guide scope and ST402 guide camera.

3 hours 40 minutes LRGB. 10 min subexposures.

http://www.pbase.com/gregbradley/image/137560511/large regular

http://www.pbase.com/gregbradley/ima...60511/original large

Anyone know of any large galaxy groupings in the Southern Hemisphere? There seems to be quite a few in the northern hemisphere.

Greg.

[Stevec35 (Steve)]

Not bad at all given the short exposure Greg. You could try the NGC 7172 group in Piscis Austrinus or the NGC 6872 group in Pavo.

Cheers

Steve

[gregbradley]

Thanks Steve.

F4.45, 17 inches of aperture and 61% QE and good seeing and "relatively" dark helps.

You got to watch the flats and gradient control with this scope though.
Its part of the compromises the designer makes - smaller central obstruction for sharper and more contrast images but more vignetting. 38% is a small central obstruction compared to the BRC250 I used which is over 50% I think. It keeps you on your toes with your gradient processing techniques though!

Thanks for the tips for the galaxy groupings.

Greg.

[Alchemy (Clive)]

I had a quick look the other day for just such a grouping, trouble is often you get elliptical galaxies, whereas you really want barred spirals to get detail, there is a grouping near ngc1365, I squeezed in 6 or so larger galaxies plus there's heaps tiny ones in there, if you frame 1365 in a corner you also get a detailed large one.

[gregbradley]

Originally Posted by Alchemy

I had a quick look the other day for just such a grouping, trouble is often you get elliptical galaxies, whereas you really want barred spirals to get detail, there is a grouping near ngc1365, I squeezed in 6 or so larger galaxies plus there's heaps tiny ones in there, if you frame 1365 in a corner you also get a detailed large one.

Thanks Clive.

I'll check that out.

Greg.

[atalas]

Nice shot Greg...lots of faint galaxies around.

[p1taylor]

That is really sum shot wonderful detail, yes there are quite a few in the northern hemisphere, only trouble is whether in UK, wish I could get that much detail in my shots.

peter

[John Hothersall]

Love these groups, imaculate stars and great colour detail around the cores, tiny fuzzies make the image so complex.

John.

[madbadgalaxyman (Robert)]

Hi Greg,

In answer to your question, one of the standout galaxy groups in the Grus region is the IC 1459 group, which is dominated by the Elliptical or very mildly S0 (i.e. large bulge with a minimal or faint disk) morphology galaxy IC 1459.

This rather bright and easy group of galaxies is rarely imaged!
It needs a very large field.

I believe that Mr Sidonio made a good image of this group of galaxies with his previous imaging rig.

It is quite rich, for a galaxy group, and it has several members with peculiar morphologies.........

IC 5264 shows interesting signs of asymmetry in its dust distribution, but it is rarely imaged at high resolution.
Here is a composite of two different DSS images of IC 5264:




NGC 7418A is a challenging and low-surface-brightness galaxy of very strange appearance that has been modelled as being the product of an interaction or a merger between galaxies.
Here is the GALEX view of N7418A in the FUV and NUV
bands :



Here is a DSS composite (of R+J plates) from the Aladin database of DSS images:





NGC 7421 is a noticeably asymmetric spiral galaxy. There is an arm or arc on one side that has the appearance of being a bow shock, but there is no corresponding feature on the other side:



(The above is a blue photograph from the "NASA Atlas" of Sandage and Bedke. The asymmetry is less pronounced in red sensitive images.)



NGC 7418 is a bright and interesting spiral, which is relatively symmetric in the bright regions of its disk, however most extant images of NGC 7418 are shallow.
Here is an image of NGC 7418 from the survey OSUBSGS :




IC 5269A and IC 5269B are also interesting members of this galaxy group.
_________________

It is hard to say how many faint galaxies may be lurking in this galaxy group, as very deep imaging of the IC 1459 group is virtually non-existent!
___________________

cheers, the bad galaxy man

[Gem (Grant)]

Originally Posted by Stevec35

Not bad at all given the short exposure Greg. You could try the NGC 7172 group in Piscis Austrinus or the NGC 6872 group in Pavo.

Cheers

Steve

Short?? It was 3 hours 40 minutes!

Nice shot!

[Stevec35 (Steve)]

Originally Posted by Gem

Short?? It was 3 hours 40 minutes!

Nice shot!

It certainly was a nice shot. Many people expose galaxies longer than that to build up the signal to noise ratio, thus enabling more aggressive processing to bring out detail in what are low signal to noise ratio objects. My normal time for galaxies is 6-10 hours.

[RobF (Rob)]

Really nice work Greg. Some wonderful colour and detail coming out in there without looking least bit overdone.

[Tom Davis (Tom)]

Another winner, Greg! You are on a roll!

Tom

[Paul Haese]

Nice Greg. That top galaxy is a pearler. There are so many galaxies in that field. I gave up counting after a while.

[gregbradley]

Originally Posted by atalas

Nice shot Greg...lots of faint galaxies around.

Cheers Louie. Yes the little faint galaxies show up often with this scope.

Originally Posted by p1taylor

That is really sum shot wonderful detail, yes there are quite a few in the northern hemisphere, only trouble is whether in UK, wish I could get that much detail in my shots.

peter

Thanks Peter. Weather is always the barrier.

Originally Posted by John Hothersall

Love these groups, imaculate stars and great colour detail around the cores, tiny fuzzies make the image so complex.

John.

Thanks John. I like these groupings as well, it makes the field more interesting.

Originally Posted by Gem

Short?? It was 3 hours 40 minutes!

Nice shot!

I know what he means. I usually do much longer as well with galaxies.
In this case it was fairly bright and the 17 inch aperture and F4.45 which is very very fast for a large scope worked in my favour. I probably will add a bit more to it to see what I can get.

Originally Posted by Stevec35

It certainly was a nice shot. Many people expose galaxies longer than that to build up the signal to noise ratio, thus enabling more aggressive processing to bring out detail in what are low signal to noise ratio objects. My normal time for galaxies is 6-10 hours.

Good point Steve. I think I will add a bit more to it to see what it does.
I was mainly imaging Comet Garradd which can't wait of course so it wsa playing second fiddle at the time.

Originally Posted by RobF

Really nice work Greg. Some wonderful colour and detail coming out in there without looking least bit overdone.

Thanks Rob. Its always a goal to try to process an image and make it look natural and like you haven't processed it at all. Not always successful in that regard but it is definitely a criterion that I keep in mind.

Originally Posted by Tom Davis

Another winner, Greg! You are on a roll!

Tom

Thanks Tom. The weather seems to have gone into clear mode at the moment and no moon - woohoo!

Greg.

[gregbradley]

You da man Robert

Thanks for those tips.

I checked out IC 1459 and what a beauty. It is also right next door to
NGC7418 so they all fit in the same FOV when I rotate my camera so they fit in the diagonal.

By the way you mentioned a while back I think it was NGC4241 (??) I went and imaged it in luminance just so you know as you were interested in it.

I should post that. I don't think I got colour though.

Thanks a million for the tips.

Greg.

Originally Posted by madbadgalaxyman

Hi Greg,

In answer to your question, one of the standout galaxy groups in the Grus region is the IC 1459 group, which is dominated by the Elliptical or very mildly S0 (i.e. large bulge with a minimal or faint disk) morphology galaxy IC 1459.

This rather bright and easy group of galaxies is rarely imaged!
It needs a very large field.

I believe that Mr Sidonio made a good image of this group of galaxies with his previous imaging rig.

It is quite rich, for a galaxy group, and it has several members with peculiar morphologies.........

IC 5264 shows interesting signs of asymmetry in its dust distribution, but it is rarely imaged at high resolution.
Here is a composite of two different DSS images of IC 5264:

Attachment 99694


NGC 7418A is a challenging and low-surface-brightness galaxy of very strange appearance that has been modelled as being the product of an interaction or a merger between galaxies.
Here is the GALEX view of N7418A in the FUV and NUV
bands :

Attachment 99695

Here is a DSS composite (of R+J plates) from the Aladin database of DSS images:

Attachment 99696



NGC 7421 is a noticeably asymmetric spiral galaxy. There is an arm or arc on one side that has the appearance of being a bow shock, but there is no corresponding feature on the other side:

Attachment 99697

(The above is a blue photograph from the "NASA Atlas" of Sandage and Bedke. The asymmetry is less pronounced in red sensitive images.)



NGC 7418 is a bright and interesting spiral, which is relatively symmetric in the bright regions of its disk, however most extant images of NGC 7418 are shallow.
Here is an image of NGC 7418 from the survey OSUBSGS :

Attachment 99698


IC 5269A and IC 5269B are also interesting members of this galaxy group.
_________________

It is hard to say how many faint galaxies may be lurking in this galaxy group, as very deep imaging of the IC 1459 group is virtually non-existent!
___________________

cheers, the bad galaxy man

[RB (Andrew)]

Gorgeous shot Greg.
Mind boggling to contemplate the treasures of the universe.

[gregbradley]

Thanks Andrew.

There are about 3 or 4 of these galaxy groupings around to be imaged now. Thanks to Robert and Steve for pointing out a few.

There seems to be a lot of imageable galaxies around the Sculptor for some reason.

I agree there are lots of treasures to be imaged.

Greg.

Originally Posted by RB

Gorgeous shot Greg.
Mind boggling to contemplate the treasures of the universe.

[strongmanmike (Michael)]

Ah the Grus trio/quartet/quintet...they are a fav huh?

Not a bad effort either

Mike

[SkyViking (Rolf)]

Mmmmmm galaxies...! Can't get enough of these
A very nice image with great colours. And 3 barred spirals in one group, that's rather cool.