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NGC 7769,70, and 71

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#1 Madratter



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Posted 03 October 2013 - 08:18 PM

I first became aware of this attractive grouping in Pegasus from an Astrobin image of the day.

I decided to take a crack at it with the Moon trending towards new. This doesn't have near enough hours in it to be great, but it serves as a good benchmark for what my C8 is capable of resolution wise.

The rather blue and circular looking galaxy with knots is NGC 7769. It is magnitude 12.5 and is 1.7'x.8' in size.

The large galaxy that is somewhat tipped is NGC 7771. It is magnitude 12.9 and is 2.5'x1.2'.

The small blueish odd shaped galaxy just over NGC 7771 is NGC 7770. It is 51"x45", and is magnitude 14.4.

Redshift places all three at about 200 million light years away.

There are a bunch of other galaxies in the field. The most interesting to me is the small spiral near the bottom. It is MCG 3-60-31 and is only 32"x27" in size. It is magnitude 16.0 in Blue and redshift would place it at 600 million light years.

Other galaxies go down to at least as far as magnitude 18.1.

This image consists of 100 minutes of 5 minute Luminosity subs binned 1x1. There are also nine 5 minute subs each in R, G, and B binned 2x2. Total integration time is thus 235 minutes or 3 hours 55 minutes. It could use a lot more integration time, especially in luminosity.


Telescope: Celestron Powerstar III C8
Mount: Orion Atlas
Imaging Camera: SBIG STF-8300m with Baader LRGB filters
Guide scope: Orion 50mm with Helical Focuser
Guide Camera: SBIG ST-i color
Acquisition Software: Sequence Generator Pro and PHD
Post Processing: PixInsight and Photoshop CS6

Imaging was done from an orange zone.

To put things in perspective, if the distance to that little spiral 600 million light years away is correct, then it is roughly 200 x further away than M33. Its surface brightness is very similar at 22.6 magnitude/arc-second squared. (M33 is 22.9 magnitude/arc-second squared so very comparable).

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#2 proteus5



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Posted 03 October 2013 - 08:28 PM

Very nice Madratter, and interesting info also. I may have to give this a try sometime I kind of like the grouping. I don't know that I can go that deep with my skies though.

#3 Thirteen



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Posted 03 October 2013 - 08:40 PM

Really cool. I like seeing these less well known groupings.

#4 Footbag


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Posted 03 October 2013 - 08:47 PM

Very nice image!

#5 CounterWeight



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Posted 03 October 2013 - 08:56 PM

What's not to like - very cool image! Especially that you have hints of the very low luminance extended 'stuff' or 'things' or whatever they are called technically. Are you going to put more time into this?

#6 Erskin71


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Posted 03 October 2013 - 09:10 PM

What I like is it was done from an orange zone. That's awesome.

#7 terry59


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Posted 03 October 2013 - 09:30 PM

I really like this. Is the image cropped?

#8 Madratter



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Posted 03 October 2013 - 09:58 PM

Thanks everyone! :)

Terry, the image is cropped. It is a 1600x1600 portion of the original, reduced to 800x800 for display here.

Jim, I would love to shoot this over again with my AT8RC. In fact, I'm trying to do that as I type this but clouds are scudding in and out and it doesn't look promising tonight. At least I got far enough, I know I can get my new scope in focus with the extension I have and what my new image scale is.

From the image of the day that I saw, it is not clear to me if that extra stuff below NGC 7771 is a tidal tail or part of the Intergalactic Flux Nebula. There certainly seems to be some interaction between NGC 7771 and NGC 7770.

#9 timtrice


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Posted 03 October 2013 - 10:23 PM

What I like is it was done from an orange zone. That's awesome.


Awesome pic

#10 Wouter D'hoye

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Posted 04 October 2013 - 12:27 AM

That's a sweet image! detail is impressive, colors are just lovely. There is till is quite some noise in the background but I'd rather see some noise than see all detail in the image washed out.


#11 TimN


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Posted 04 October 2013 - 11:07 AM

This is really nice Madratter. Its nice to see unusual stuff here. More time on it would reduce the noise and keep the detail. With the weather - easier said than done.

#12 Madratter



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Posted 04 October 2013 - 11:08 AM

Thanks Wouter. And I agree about the noise.

#13 raf1



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Posted 04 October 2013 - 11:34 AM

You're right, just needs more time. A heck of a good start nonetheless.


#14 lawrie



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Posted 04 October 2013 - 11:37 AM

What a good start, hope the weather cooperates and you can get more integration , how much more time do you think?

#15 Madratter



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Posted 04 October 2013 - 12:01 PM

Thanks Ron and Lawrie.

I'll start over with my new AT8RC if the weather will cooperate. I'd like to get at least four and preferably eight hours of luminosity data on this one.

#16 HT417



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Posted 06 October 2013 - 03:43 AM

That's an inspiring photo. :bow: :bow: Hopefully, I can get to that level one of these days.

#17 Jeff2011



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Posted 06 October 2013 - 11:39 AM

A very nice galaxy rich field. Looks great even being viewed from my iPhone. Can't wait to see the RC version. How about combining the data from both scopes?

#18 Madratter



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Posted 06 October 2013 - 03:56 PM

Thanks HT and Jeff. HT, you can definitely get to this level if you want to. I've been doing this actively for less than a year. Some of it is technique, some of it is equipment.

Jeff, I won't be adding to this with the new scope. The new data is way better. I was able to catch 30 minutes of useable luminosity data the other night before things shut down. This is the center and corners from that data. This is just as sharp and was shot at f/5.86 (1190mm) instead of f/10 (2032mm). The corners are hugely better despite being a much wider field.

Unlike the above, this has no deconvolution applied. It is simply calibrated, registered, stacked, gradients removed, and then a simple histogram stretch.

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#19 JazzSky


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Posted 06 October 2013 - 04:26 PM

Great image. Makes me want to break out my C8 again.
Thanks for sharing

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