Grus western Triplet 7162, 7162A, 7166, and 130 friends
Another, different, trio in Grus. NGC 7162A is the large, bright blue, face-on star-burst disrupted spiral toward 11 o'clock. The very bright, dominant featureless orange elliptical toward 7 o'clock is NGC 7166, and the prettier, more normal half-face-on spiral toward 4 o'clock is NGC 7162. So (with North up) that makes 4711.
These fellows are not as bright as the more famous Grus triplet. This exposure is 24 hours of Luminance, and 3 hrs each of RGB, all in 1 hr subs.
The color contrast between the disrupted spiral and the elliptical is very obvious, and took little encouragement to show.
The field shows 130 background galaxies that are obvious because of their shape - mostly distant edge-on spirals. If there are that many edge-on spirals, my guess is that rather a lot of the amorphous orange blobs are distant ellipticals, especially where they seem to cluster into family gaggles.
At the extreme top left of the original image (not the cropped low-res thumb) is a set of four galaxies, two of which are in a deadly embrace, and shedding long tidal tails as they dance toward union.
Aspen CG16M on 20" PlaneWave. All processing in GoodLook 64. Field 36 min arc, 0.55 sec arc/pixel.
That's fantastic MnT, love the giant elliptical and the galaxy at the top of the frame that kinda looks like a cross between an irregular dwarf and a disrupted spiral.
Wow, lots of interesting finds in the background. Do you know what the smudge in the middle of the far left is? Or what the green blob roughly 2/3 from center to top right is? I've attached small crops from these regions.
Wow, lots of interesting finds in the background. Do you know what the smudge in the middle of the far left is? Or what the green blob roughly 2/3 from center to top right is? I've attached small crops from these regions.
That smudge looks like an irregular galaxy. As for the green "star", I am thinking red shifted luminous object. A quasar could potentially be the culprit. Could always plate solve the region and get exact coordinates on that blob.
When exploring the image, my imagination was activated and I could almost see the Startrek somewhere in there, searching for its way home...
As for the technical side, 1hr subs at 0.55 arcseconds per pixel... I will keep on dreaming
Thanks muchly, Suavi. Hope we haven't over-sharpened it. Perhaps half a tad.
The question of how long an exposure is best for us is still slightly unanswered. I often wonder if some photo-electrons that one has captured early in an exposure ever leak away late in the exposure. Hope not.
Quote:
Originally Posted by Stevec35
Nice and colorful. Just how I like it.
Cheers
Steve
Thanks Steve!
Quote:
Originally Posted by RickS
Very cool, M&T! The small intriguing fuzzies in that region are shown in great glory NGC 7162A is a fascinating object.
Cheers,
Rick.
Thanks Rick. There were more than we expected. The two colliding galaxies were a bonus.
Quote:
Originally Posted by el_draco
Cripes, there's a lot of galaxies in the background. Very cool!
Cheers, Rom. Nice to hear from you.
Quote:
Originally Posted by Atmos
That's fantastic MnT, love the giant elliptical and the galaxy at the top of the frame that kinda looks like a cross between an irregular dwarf and a disrupted spiral.
Thanks Colin. Agreed.
Quote:
Originally Posted by mountainjoo
Wow, lots of interesting finds in the background. Do you know what the smudge in the middle of the far left is? Or what the green blob roughly 2/3 from center to top right is? I've attached small crops from these regions.
Hi, Jerome. We agree with Colin's comment that the blob toward 9 o'clock is almost certainly a dwarf galaxy which just happens to have a couple foreground stars confusing the picture. We're also tempted by Colin's explanation that the aqua star could be a quasar. We once photographed a galaxy in Libra which had nineteen catalogued quasars in the image. They tended to be implausible super-saturated blues, which made them easy to find. Dunno. Could be just an artefact.
Quote:
Originally Posted by p1taylor
That is really good.
peter
Hi, Peter, Lovely to hear from you. Glad you like it.
Quote:
Originally Posted by Atmos
That smudge looks like an irregular galaxy. As for the green "star", I am thinking red shifted luminous object. A quasar could potentially be the culprit. Could always plate solve the region and get exact coordinates on that blob.
Thanks Colin - we think your explanations are very good. Don't have any super-good plate solving capability against a big catalogue. Next free moment I'll plate solve roughly against Tycho, find the coords of the probable galaxy, and see what I can find. Anyone beats me to it, so much the better.
This shot was interesting in that even after 3 nights (over two consecutive rainy months) it was looking pretty boring, but yesterday we added just 9 hours of colour, and Hey, Presto! it looked much more endearing.
Wow, such a busy field here. I might be able to plate solve in PI in next 2 hrs. Can't wait!
Thanks for your efforts, Simmo. Would love to see the result. (I actually bought and paid for PI, but never learned how to get the mathematical shrink-wrap off).
Our image centre is approximately 22:02:16 -43:06:56 +/-10 sec arc pointing error.
Jerome's 9 o'clock object is definitely an obscure galaxy. Simbad lists it as AM 2158-433 but it probably has aliases.
The aqua blob toward top right is at 21:59:25.8 -43:04:08.3, where Simbad shows an unnamed star of indeterminate coolish colour. So not an artefact. Sadly, the nearest quasar listed in the MilliQuas million quasar catalogue is about three fields away. However, it is a sparse catalogue.
took quite a few different attempts before I could get it to solve, before I finally thought 'hmm, magnitude 12 might be too low a limit, I bet these deep images are greater than 12. 21 did it
Galaxies anyone? GALAXIEEEES... GET YA GALAXIEEEES!
The Grus part of the sky is such a great place for background faint fuzzies, they seem to just keep going on and on in the background of most galaxy shots of the region
Galaxies anyone? GALAXIEEEES... GET YA GALAXIEEEES!
The Grus part of the sky is such a great place for background faint fuzzies, they seem to just keep going on and on in the background of most galaxy shots of the region
Could that blue spot be a planetary neb..?
1hr subs, love it
Nice work
Mike
I had considered that, would have to be a very strong OIII emission (pretty close in colour being tealish) and either very small or VERY far and bright.
took quite a few different attempts before I could get it to solve, before I finally thought 'hmm, magnitude 12 might be too low a limit, I bet these deep images are greater than 12. 21 did it
Lovely! We're going to have to learn how to do that.
Quote:
Originally Posted by strongmanmike
Galaxies anyone? GALAXIEEEES... GET YA GALAXIEEEES!
The Grus part of the sky is such a great place for background faint fuzzies, they seem to just keep going on and on in the background of most galaxy shots of the region
Could that blue spot be a planetary neb..?
1hr subs, love it
Nice work
Mike
Cheers, Mike! Could be a tiny/distant PN. IC5148 is just round the corner. Shows it can be done!
Happy to show you via pm, if Google doesn't help it sink in. You need to save the image in FITS format after doing the solve, then use Annotate Image to display the labels
We agree with Colin's comment that the blob toward 9 o'clock is almost certainly a dwarf galaxy which just happens to have a couple foreground stars confusing the picture. We're also tempted by Colin's explanation that the aqua star could be a quasar. We once photographed a galaxy in Libra which had nineteen catalogued quasars in the image. They tended to be implausible super-saturated blues, which made them easy to find. Dunno. Could be just an artefact. 
