NGC6902 / NGC6902B / IC4946 - Galaxy Group in Sagittarius

[SkyViking]

Hi All,

I felt it was time to again pick some galaxies after my recent dabbling in bright nebulae - and even in Sagittarius one doesn't have to wander far off to find some obscure targets, so here are 17 hours on a beautiful but almost unknown galaxy group:

Link to large image (3MB) (http://www.rolfolsenastrophotography.com/Astrophotography/Galaxies/25329559_xL3ckk#!i=2738537774&k=nfcjpm5&lb=1&s=X3)

About the image:
In the far south-eastern corner of Sagittarius, a constellation otherwise known for its spectacular highlights near the crowded Milky Way centre, lies the very rarely imaged galaxy NGC 6902 and a couple of its neighbours. Despite its beautiful and elegant appearance there is very little information about this galaxy to be found anywhere.
It contains a bright central ring and possibly also an elusive inner bar. The spiral arms are quite faint despite almost 17 hours of exposure, which is indicative of a rather weak population of O type stars. The arms also have a knotted appearance, perhaps due to the presence of brighter HII regions located within them.
The galaxy lies approximately 33 million light years away and was discovered by John Herschel.
A number of other galaxies can be seen scattered across the field of view, including the smaller face-on spiral NGC 6902B to the upper left. At the top of the frame lies edge-on galaxy IC 4649 with some traces of obscuring dust and a hint of a bar structure surrounding its core.
And far in the background countless distant galaxy groupings can be seen as small fuzzy yellowish dots throughout the image.

Image details:
Date: 29th July, 5th, 6th, 7th, 8th and 9th August 2013
Exposure: LRGB: 645:152:122:93 mins, total 16 hours 52 mins @ -30C
Telescope: 10" Serrurier Truss Newtonian f/5
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand

I hope you enjoy the view of this rather obscure piece of sky :lol::P

Regards,
Rolf

[John Hothersall]

This is very off the track image and an eyeopener. The tail of Sag also contains M55 giant glob, 2 terzans and ARPGC2 cluster and the curious 6845 galaxy quartet in Telescopium, but is relatively unimaged. Sag tail is packed with galaxies.

Great detail in the small spiral and other galaxies as well as star colour as usual.

John.

[RobF]

The only thing you could do to surprise me Rolf is post a boring image ;)
Beautiful field, and not one I'm familiar with. Beautifully rendered too BTW. Thanks for sharing.

[pmrid]

Stunning stuff Rolf. Beautifully presented. Thank you.
Peter

[RickS]

Very cool field, Rolf. Well done!

[strongmanmike]

That's great Rolf and looks lovely on my new spiffy monitor too :thumbsup: I love the fine outer arms of the spiral NGC 6902. Actually, it's a reasonably small galaxy according to the LEDA data base at 5.6' X 4' but I recon you may have revealed a bit more than that in your image!?

Great stuff...galaxies in Sagittarius huh? Niiice :lol:

Mike

[gregbradley]

A beautiful image Rolf. That's quite stunning.

Greg.

[Larryp]

Great image, Rolf!

[Lee]

That's great work.... I never really thought of galaxy clusters in an area like Sagittarius.... I'm surprised the image isn't drowned out with Milky Way!

[SkyViking]

Thank you John, I was just cruising around looking for something different and stumbled upon this one. You've listed some other interesting targets thanks, maybe it's time to go hunting :)


Thanks very much Rob for your kind words! :)


Thank you Peter, it's a nice galaxy indeed.

Thanks Rick, I felt the need for a galaxy field after the nebula season :) Well at least that season is mostly over for me anyway since the Milky Way is now coming close to the trees in the west when viewed from my location.

Thank you Mike, I thought you'd be happy with this field :)
I was surprised with how faint those outer arms were, but yes there are some obvious extensions and one in particular reaching almost up to the orange star. That structure looks a bit distorted too, which is interesting.

Thanks a lot Greg, I'm glad you liked it :)

Thank you Larry :)

Thanks Lee, I didn't really consider Sagittarius to be a hunting ground for galaxies, but this particular corner seems to be. It wasn't until I looked for info about the galaxy that I found out how little is written about it. :eyepop::lol:

[Paul Haese]

Love that spiral. Very nice and the star colour is lovely Rolf. A bigger image would be nice to surf through.

[Octane]

Oh, my. Rolf, that image just took my breath away.

Spectacular.

H

[allan gould]

Rolf, what a beautilful image. Fantastic result but I expect that from you.
Allan

[David Fitz-Henr]

Yeah, beautiful field chock full of galaxies! Nice colour processing on the stars and galaxies as well. One small point - the stars look slightly elongated left / right, is this a guiding issue?

[LewisM]

En meget provokerende og ærefrygtindgydende billede Rolf!

[naskies]

Whoa, you never cease to impress and amaze Rolf ;)

[Ross G]

A beautiful photo Rolf.


Ross.

[multiweb]

Wow! Beaute field Rolf. Excellent shot. Sharp as. :thumbsup::thumbsup::thumbsup:

[Stevec35]

Great stuff as usual Rolf. Never seen this group before.

Cheers

Steve

[Suzy]

Phoarwwwww! Way awesome, Rolf!
I love that you photograph the unusual!

And I echo what Rob F said so well:

Rolf, I've just popped this on the IIS fb page (https://www.facebook.com/photo.php?fbid=10151844631401203&set=a.443095681202.235512.114571796 202&type=1&theater) along with a plug for your poster purchases. :)

[jase]

What a picturesque scene, Rolf! I enjoyed swimming around the original size image looking at the background galaxies. Aesthetic colours to boot makes for an all round visual treat. Thanks for sharing. Looking forward to seeing more of your work.

[pvelez]

Rolf

galaxies in Sagittarius - who would have thunk it

A beautiful image. So many galaxies to wander amongst.

Pete

[Shiraz]

very attractive image Rolf - lots of interesting stuff to look at. regards Ray

[SkyViking]

Thank you Paul. You can access the full resolution image here (http://www.rolfolsenastrophotography.com/Astrophotography/Galaxies/25329559_xL3ckk#!i=2738537774&k=nfcjpm5&lb=1&s=O).

Thanks very much H, I was surprised with how well it turned out. I really just wanted to image something off the beaten path again and stumbled across this little group.


Thank a lot Allan - now the pressure is on it seems! :P:lol:


Thanks David, yeah I think I need to take the G11 apart and give it a tune-up soon. I plan to do that when I install my new 12.5".


Mange tak Lewis, jeg vidste ikke du taler saa godt dansk! :lol:


Thank you Dave! :)


Thanks Ross! :)


Cheers Marc, I think the 17 hours helped as well. A standard image for me is usually around 10 hours, but I decided to go a bit further on this one since the spiral arms were so faint.


Thanks Steve, neither had I :) I really enjoyed taking and processing this image, and the fact that there turned out to be so little info available on these galaxies only added to the excitement.


Thanks a lot Suzy, you're too kind :)
...If anyone wants some posters you all know where to go ;):P
I have to say these look really awesome, not because they are my images but because large format deep sky posters just simply rock :D
I remember I had two astro posters in my room as a child. My parents bought them in the Tycho Brahe Planetarium in Copenhagen. One was with the Trifid and the other was the Andromeda galaxy. I loved staring at them all the time. I still have them rolled up somewhere, and it's interesting to notice that most images posted here on the forum are now way better than those professional images that I gazed at in awe 25 years ago! :thumbsup:


Thank you very much Jase, I'm glad you liked it! :)


Thanks Pete, yeah it wasn't the first place I'd expect to find such a scene :lol:


Thank you Ray, yes there is a lot of stuff in the background too, most of the tiny faint yellowish dots are distant galaxies.

[Leonardo70]

Stunning shot.

Congrats,
Leo