Grus galaxies - the don't bring me down cluster*

[RickS]

* Astrofest in joke ;)

Capture:
Taken at Qld Astrofest 30 June to 5 Aug 2016

Objects in image:
NGC7599, NGC7531, NGC7590, NGC7582, NGC7552, Abell 1111, and 800+ PGC galaxies

Scope: AP140EDF/reducer = 771mm FL
Mount: AP900
Camera: U16M
Filters: Astrodon E series Gen 2 LRGB, 3nm Astrodon Ha, 3nm Astrodon Oiii
Guiding: Lodestar / Borg 50mm guide scope
Image scale: 2.41 arcsec/pixel (drizzled to 2x then reduced to 75%)
Exposures: 36x600s L, 14x900s R, 12x900s G, 12x900s B (15.5 hours)
Processing: PixInsight 1.8

The attached image is a small crop as it is difficult to reduce this to a 200Kb jpeg. Higher res larger crop on Astrobin: http://www.astrobin.com/full/260775/B/ It's worth zooming around the full res version.

Hope you enjoy the image and I always appreciate constructive criticism :)

Cheers,
Rick.

[el_draco]

That's a Dr Who view! Drop dead gorgeous :eyepop:

[topheart]

Hi Rick,
That's majestic! Well done.
How small we are....

Can I ask what you do exactly with the drizzling of data such as this.
Thanks,
Regards,
Tim

[atalas]

That's a great short Rick:thumbsup:that galaxy lower left,is that tidal tales showing?

[RickS]

Thanks, Rom.



Thanks, Tim. We are small indeed!

When significantly undersampled, I use drizzle integration to increase the resolution, usually by a factor of two, and then downsample when I finish processing if the data doesn't quite hold up at full res. With the AP140 set up at 2.4 arcsec/pixel I'm invariably undersampled even in terrible seeing. This time I doubled the res and then did a final resample at 75% to give a 50% resolution increase over the original data.

Hope that answers your question?



Thanks, Louie. I thought that was a reflection initially but it has a PGC number so I think it's yet another galaxy. There are supposed to be some faint tidal tails between members of the quartet and I was hoping to capture them but I can't see them even with averted imagination :lol:

[Camelopardalis]

Erm...the background just looks a little too black... ;) :lol:

Just kidding...looks stunning Rick :thumbsup:

[strongmanmike]

Bah! easy for me, clear as day those tidal streams :D :rofl:

Another great wide field galaxy shot Rick, always fun to peruse such fields looking at all the cool bits and this field has sooo many galaxies, well done :)

Mike

[atalas]

Hi Rick

Yeah I ask dude because I would of thought It to be quite difficult at this scale....I never look at maths behind these things...just easier to ask....too lazy.

[topheart]

I was more asking about the steps in PI within the Star Alignment module.....Does the final re-sample equate to the "drop shrink"??

Thanks,
Tim

[jjjnettie]

:) An image of epic proportions.
Jeff Lynne would be proud.

[RickS]

You could be right, Dunk. I'm never quite sure if I've gone too far either way... at least until a few days later when I'm sure I got it wrong :)



Ta, Mike. Your rendition from ages ago (2009?) was a bit of an inspiration for me and still looks damn fine :thumbsup:



With this fairly fast combination of scope and camera I thought I'd have a good chance of pulling out any faint detail like that, Louie, but I got a bunch of IFN (which I didn't try to push this time around) and no tidal tails. I've not seen any images that show them so maybe they are really faint or maybe even nonexistent :shrug:



I used DrizzleIntegration with a Scale of 2 and adjusted Drop Shrink to taste (the default of 0.9 was good this time.) That gave me double res data (8192x8192 pixels) which I processed to completion. Then I used the Resample process at 75% to downsample the final image.

Cheers,
Rick.

[RickS]

Thanks, JJJ :rofl:

[Placidus]

Such a rich field, Rick. Running out of superlatives. Beautiful colour and contrast - a jewel-box of galaxies.

[RobF]

You got me runnin' goin' out of my mind Rick!

Top shot. Wonderful view of this cluster.

[Atmos]

The detail in all of those galaxies is extraordinary! You mentioned you were a bit worried about the colour version not being as well as the straight luminance, nothing to worry about there!

[Retrograde]

Beautiful dEtaiL in thOse galaxies Rick.

[RickS]

Thanks, M&T!



Ta, Rob :lol:



Thanks, Colin. I'm pretty happy with the end result but it took some work to get there. Just occasionally an image comes together really quickly and easily but this wasn't one of those :)

[RickS]

Nicely done, Pete :lol:

[jjjnettie]

It makes us feel like we're wasting our time with our little scopes and cameras.

[billdan]

Congratulations Rick, truly awesome image, I remember the luminous version you posted up recently. But the colour version is just "out of this world".

Cheers
Bill

[ozstronomer]

Beautiful image Rick, a magnificant FOV with so many galaxy's

Well done :thumbsup:

[RickS]

Not at all, JJJ! It's great to see the diversity of images from different people with a variety of gear. That's one of the cool things about this pursuit - even the most basic equipment can produce stunning results.



Thanks, Bill.



Ta, Geoff!

[marc4darkskies]

Beautiful Rick! A lovely field to wander around in. :thumbsup::thumbsup:

[multiweb]

Epic field! :thumbsup: :whistle: Grusss... :whistle:

[RickS]

Thanks, Marcus.



Thanks, Marc :lol:

[IanP]

Great shot, Rick ... looks really stunning :hi:

[willik]

That is amazing shot very good detail.

[Regulus]

That's truly beautiful Rick. Still going back to the hi-res and getting lost in it.
Well done.

Trev

[gregbradley]

That's a fabulous image Rick.

These widefields are very immersing. That galaxy on the lower left side is interesting. It looks like a whitish galaxy area below a regular looking spiral. A collision or extended halo perhaps?

Greg.

[CJ]

Stunning. Just stunning! :eyepop:

[RickS]

Thanks very much, guys!



Thanks, Greg. I thought that was a reflection at first but it appears to be PGC 70787. I haven't been able to find much info but there is a paper "Dynamics of the Pavo-Indus and Grus cloud of galaxies" that describes it as "a strange object at 2.9'E from NGC 7531. It is not a plate default as it appears on red and blue films, as well as SERC films."

Cheers,
Rick.

[alan meehan]

my goodness Rick thankyou very much one of the best I have seen ,seems ill have to practice more
AL

[RickS]

Thanks, Al. I'm going to keep practising too :thumbsup:

[vlazg]

A beautiful image Rick, so much detail to absorb, can spend ages.

[RickS]

Thanks, George!

BTW, attached is a full res crop of NGC 7531 showing an inverted image of the odd "galaxy" PGC 70787 beneath. I pinged a friendly astrophysicist and he pointed me at an article that suggests this is a stellar tidal stream associated with NCG 7531 rather than an independent irregular galaxy.

Cheers,
Rick.

[codemonkey]

Nice work Rick. My personal take is that it's pushed harder than the data can support, but it was nice to cruise around and check out all those background fuzzies, which of course wouldn't be as apparent had you not pushed the data so hard.

[Stevec35]

I don't think I've seen a better shot of that region Rick. Nice work.

Cheers

Steve

[RickS]

Ta, Lee. I could have dropped the resolution further or stretched the faint stuff less and ended up with a cleaner image but it was a deliberate choice.



Thanks very much, Steve!

[Somnium]

Really great image Rick, i love shots like this, just surfing around to see those faint fuzzies, fantastic. Though, are you sure Abell 1111 is in this view, looking in TSX, that galaxy cluster is around RA 10h 51m and Dec -02 39' but the Grus quart is around 23h 19m and -42 18'

[Shiraz]

Ripper image Rick - lovely to be able to see so much interesting stuff in one frame.

[RickS]

Thanks, Aidan. Looks like Abel 1111 was incorrect. The galaxy cluster in the FOV is actually ACO 3998.



Thanks, Ray!

[Kunama]

Beautiful image Rick !!! we were viewing this at Coolah on the weekend under near perfect conditions.....

[RickS]

Thanks, Matt! What scope were you using? It was interesting looking through the big dobs at Astrofest though I'm not a huge fan of ladders in the dark, especially as imagers like a drink or two to ward off the cold ;)

[Kunama]

We had Shane's Meade 10" LX, Allan's Zambuto powered XT12G? and my 18"F5.6 with Galaxy Optics mirrors.

[RickS]

Nice! How did they compare, Matt?

[Kunama]

We mostly had each scope pointing at different targets with different eyepieces and were swapping views so did not really do direct comparisons.

[RickS]

That's a nice way to observe!

[PRejto]

I'm late to the party to comment on this very striking image. However, it really is outstanding and hypnotic. Refractors rule.

Peter

[Fabiomax]

What a wonderful field! Also interesting for the physical implications of galaxies! I went to look for it on the planetarium, but to me it is too low! I console myself with your beautiful picture.
Cheers,
Fabiomax

[RickS]

Thanks, Peter. I do enjoy imaging with the AP140!



Thanks, Fabiomax! You have many cool objects that we can't image so that seems fair :lol: