Gravitational Galaxies in Grus

[jase (Jason)]

Hi All,
I’m pleased to present “Gravitational Galaxies in Grus”, the latest collaborative effort between Alvin of Lightbuckets and myself. This area of the night sky has intrigued me for sometime due to the interesting characteristics of the interacting triplet.

About the target;
Located in the constellation Grus, three spiral galaxies located very close to each other interact. When galaxies are close enough, a mutual gravitational attraction can result, often altering the appearance and in some cases the composition of their systems. An example of this is the galaxy center of frame, NGC7582. This barred spiral galaxy exhibits tidal tails extending towards the two neighbouring galaxies (NGC7590 and NGC7599) at top left and another galaxy below which is not present in the frame (NGC7552).

About the image;
The image is a straight LRGB composite with a total exposure time of 12.6 hrs (L:260min,R:160min,G:150min:B:190mi n). Data acquisition performed by Alvin on the Lightbuckets 14.5” RC (3315mm F/9) in Pingelly, WA. He came up with a unique composition of the trio which has progressively grown on me, with the center showpiece being NGC7582. The other interacting galaxies (NGC7590 and NGC7599) add a nice dimension at top right of frame. The “void” to the lower right diverts ones attention and allows the numerous faint background galaxies to really come through, offers an interesting perspective. As the RC FOV is small, the forth member to complete the quartet, NGC7552 is off the frame. A mosaic at this FL would have been magical. I took a basic approach to processing this image with the goal of maximising the background galaxies and displaying a natural colour saturation of the foreground objects. After the usual calibration, registration and creation of masters, I duplicated the luminance data and pushed it through to different iterations of deconvolution. The first was relatively light, while the second luminance was strong. The latter revealed some incredible features on the oversampled data, but destroyed stellar profiles. The lightly deconvoluted image simply provided tighter stars and was used as the main luminance. This was heavily stretched in DDP before being imported into PS to bring out the faint background galaxies. The quality data stretch quite well, with very little noise exhibited. The stronger deconvolution was simply imported straight into PS and introduced using a mask at 30% opacity. I blurred the mask to provide a smooth transition. This provided control of the integration of the rich details for the three foreground objects. The two layers were flattened with a very light USM applied. Similarly, two copies of the RGB combined master were created. One imported directly into PS and was stretch manually using levels and curves. This was also adjusted to get the colour foundation correct. The luminance was then introduced at 60% opacity. The second RGB master had its saturation boosted to ~190% and pushed through a hard DDP stretch, almost to the point where highlight clipping was experienced. This master was imported into PS and introduced as a softlight blend at approximately 70%. Luminance was then increased to 85%. Minor colour balance tweaks applied to manage the softlight blend impact to the layers. The softlight blend layer had the minimum filter applied with the fill effect dropped back to 25%. Yes, you heard…I used the ghastly minimum filter, but when used appropriately, it can work wonders. This gave a richer appearance to star colours. A minor gradient from the green channel was experienced along the lower parts of the frame, but cleaned up with GradientXterminator. The image was then flattened and black point set appropriately. While its tempting to make the background ultra dark to maximise the faint background galaxies, this resulted in too much contrast for this image, leading to an unnatural transition between features. Minor noise reduction invoked via invert mask. Could have perhaps gone harder.

I’d like to thank Alvin for the opportunity to process this data set. The area has been on my seasonal target list for sometime, but never intended to nail it at 3315mm FL. The image scale delivered by the FL provides some “punchy” details on the triplet.

Couldn’t think of a better way to mark the 2,000th post than with a pleasing image to share amongst like-minded souls. Anyway, enough yabbering. Thanks for having a look - I hope you enjoy as much as I did processing it! All comments welcome.

[AlexN]

Happy 2000th post, and yes, it was used to perfection!

Nailing anything at 3315mm FL is a fair feat! Processing, colors and detail are all fantastic! Very nice indeed.

[strongmanmike (Michael)]

Not bad Jase, the Grus trio is really a favourite of many of us down under huh?

Now you are always honest with me "and" you are using the best and have great skills and I know ya like it straight and in minute detail ... soooo I am gunna be brutally honest

Overall an interesting image and had it been done on an ordinary backyard scope I would be reasonably impressed and say so but while the image is certainly quite nice it lacks any wowyness this time, something that 13hrs on an expensive automated commercial telescope probably needs to offer in my mind to validate the cost...but anyway if money isn't in the equation so be it.

The image is certainly smooth but at the 2400X1800 size it deffinitely has that just-a-bit-too-long focal length for the aperture and seeing conditions (breath) so lots of processing was necessary, look to it. The 1600 X 1200 size looks the best. The colours look just a little dirty and mute to me too with the galaxy cores having a strange and somewhat mute burned orange colour and the arms are a funny muted blue colour . There is certainly some nice detail and you have clearly put a bit of processing work into it but I think the focal length and seeing probably just weren't quite in agreement on this outing as the detail or feature deliniation isn't as good as would perhaps have been expected from this configuration? For comparison here is a simple 60min of Lum on the trio with a 6" F7.5 1140mm FL scope from suburban skies (ignore the un-flatted dust donnuts) with only DDP applied and no other processing....there isn't much difference in the res to me?

http://www.pbase.com/strongmanmike20...54137/original

Don't get me wrong it is a pleasing image and well worth the look (thanks) but it's just not what I would be happy with for the cost of producing it, hope that doesn't sound too rude..? again had it not been done with an expensive Pro outfit I wouldn't have been so critical and many will find it pretty good anyway (cause it is) but in this case when you are using the best, paying for it and promoting it, hey, we wanna see the bluddy best man!

Mike

[Dennis]

Hi Jase

What an astonishingly captivating image! The detail in the “quartet” trio is quite breathtaking and very nicely processed right down to their cores.

What really bowls me over is the grand vista of the 2400x1800 version, despite having to scroll around my postage stamp sized 1600x1200 monitor!

The plethora of background galaxies is really quite extraordinary; the obvious ones reveal their identity somewhat readily via their non-stellar extension, but there are numerous stellar-like galaxies which give themselves away by their softer profiles compared to the real stars. It’s almost Hubble deep field!

Congrats on the 2000th post – what a way to join the club. As always, thanks for the processing narrative – it’s almost like having a tutor at your elbow.

Cheers

Dennis

[strongmanmike (Michael)]

Hi Jase

What an astonishingly captivating image! The detail in the “quartet” trio is quite breathtaking and very nicely processed right down to their cores.

What really bowls me over is the grand vista of the 2400x1800 version, despite having to scroll around my postage stamp sized 1600x1200 monitor!

The plethora of background galaxies is really quite extraordinary; the obvious ones reveal their identity somewhat readily via their non-stellar extension, but there are numerous stellar-like galaxies which give themselves away by their softer profiles compared to the real stars. It’s almost Hubble deep field!

Boy, great Dennis I feel like a right nitt picking woser now .....Hopefully Jase won't take me too seriously?

Congrats on the 2000th post

2000 huh?? not bad!...Image the total number of words though

As always, thanks for the processing narrative – it’s almost like having a tutor at your elbow.

I must be a bit slow? or just plain .. cause it usually just confuses the begeezus outta me

Cheers

Mike

[AlexN]

Originally Posted by strongmanmike

2000 huh?? not bad!...Image the total number of words though

Haha... Let me do the math on that.... mumble mumble... carry the 4.....?? Bazillions of words???

They sure are some long posts, but not one word more or less than is required to explain everything perfectly.

[Peter Ward]

Commendable processing effort Jase, though I too suggest the seeing has not helped the data. The image lacks a little colour or "punch" (sorry hard to quantify) for my taste. Interestingly, the background shows no colour noise at all

I've found nights that allow any 12" or larger scope to truly perform are rare indeed. None-the-less beautifully round stars, at over 3 metres FL, is no small feat.

[strongmanmike (Michael)]

Ok Ok ...I had another good look Jase and expensive scope time aside, it is a very nice image. The three main galaxies are pretty small I guess and it is a very small field, so yep...not bad

First impressions are important though...your Crab was really good

Mike
trying not to sound like a stick in the mud

[Jen]

beautiful pic Jase i would be happy to be able to see these in my scope let alone be able to take a pic of it nice work

[jase (Jason)]

Feedback is invaluable - I always listen to critiques. As such, I've presented the alternate version based on some feedback - not all, as there are aspects of the image I like. The same link can be used to view this rendition, my apologies to those who did not get to see the original to make a comparison. I should clarify that I did not reprocess the image from scratch. This is one of the many renditions I had created, but wasn't happy with some aspects. I have since remedied these as a result. Whether or not I've hit the mark expected of others is not the goal, but more the value of thought provoking feedback.

Two main differences have resulted. I added a third stronger deconvolution layer and HPF mask to give the galaxies further definition. Secondly, I duplicated the base RGB layer, moved to the top of the layer stack as colour blend mode. Then performed two iterations of shadow/highlights to both stretch and colour saturate the data. This has provided a subtle colour boost, in particular brought out the HII regions and dust lanes. I don't think this is the most optimal way, but in processing, there is always more than one way to get the same result. The image has been reduced to 71% of original size to give you are larger FOV (equals more of those noteworthy background fuzzies).

Originally Posted by AlexN

Happy 2000th post, and yes, it was used to perfection!

Nailing anything at 3315mm FL is a fair feat! Processing, colors and detail are all fantastic! Very nice indeed.

Thanks Alex. I didn't realise I was approaching the post milestone until yesterday. Just so happens that I was working on this image over the past week and both coincided. Pleased you liked the image.

Originally Posted by strongmanmike

Now you are always honest with me "and" you are using the best and have great skills and I know ya like it straight and in minute detail ... soooo I am gunna be brutally honest

I can take it Mike, if I couldn't, I wouldn't be posting the image to this forum.

Originally Posted by strongmanmike

The colours look just a little dirty and mute to me too with the galaxy cores having a strange and somewhat mute burned orange colour and the arms are a funny muted blue colour . There is certainly some nice detail and you have clearly put a bit of processing work into it but I think the focal length and seeing probably just weren't quite in agreement on this outing as the detail or feature deliniation isn't as good as would perhaps have been expected from this configuration?

Good feedback in which I've taken aboard (and "attempted" to remedy). I have to say, overall the data was pretty good.

Originally Posted by strongmanmike

For comparison here is a simple 60min of Lum on the trio with a 6" F7.5 1140mm FL scope from suburban skies (ignore the un-flatted dust donnuts) with only DDP applied and no other processing....there isn't much difference in the res to me?
http://www.pbase.com/strongmanmike20...54137/original

Theoretically, you have better sampling for the conditions at 1.13 arcsecs/pixel - while I doubt you'd be getting that resolution at the cover slip. The 14.5" RC is delivering 0.56 arcsecs/pixel even less than ideal, but what the RC delivers is image scale which is the right recipe for those distant galaxies. I haven't blinked the two images for a closer analysis and not sure how valid this would be given processing distorting the result.

Originally Posted by strongmanmike

Don't get me wrong it is a pleasing image and well worth the look (thanks) but it's just not what I would be happy with for the cost of producing it, hope that doesn't sound too rude..? again had it not been done with an expensive Pro outfit I wouldn't have been so critical and many will find it pretty good anyway (cause it is) but in this case when you are using the best, paying for it and promoting it, hey, we wanna see the bluddy best man!

Ah Mike, you make the assumption that using the best, delivers the best. If I could be assured that on an expensive pro outfit that I would get quality subs every time and in turn produce wow factor images one after another, I'd be refinancing and standing in line to purchase one (along with everyone else). We both know there are many other factors that can alter the end result.

Appreciate the feedback Mike. Thanks again.

Originally Posted by Dennis

Hi Jase

What an astonishingly captivating image! The detail in the “quartet” trio is quite breathtaking and very nicely processed right down to their cores.

What really bowls me over is the grand vista of the 2400x1800 version, despite having to scroll around my postage stamp sized 1600x1200 monitor!

The plethora of background galaxies is really quite extraordinary; the obvious ones reveal their identity somewhat readily via their non-stellar extension, but there are numerous stellar-like galaxies which give themselves away by their softer profiles compared to the real stars. It’s almost Hubble deep field!

Congrats on the 2000th post – what a way to join the club. As always, thanks for the processing narrative – it’s almost like having a tutor at your elbow.

Cheers

Dennis

Cheers Dennis. I'm certainly pleased with the way DDP handled the faint background galaxies. I don't often use DDP for luminance stretching, but having done some additional reading on its function and mid level adjustment, I'm beginning to get more comfortable with it. I don't incorporate any sharpening as part of the function as I prefer greater control. As you indicate, the background galaxies resolve quite well, even the faint companions. DDP is quite magical in the way it can enhance and/or suppress dynamic range. Thanks too for the 2,000th post congrats - beginning to feel like a part of the furniture! Thanks again.

Originally Posted by AlexN

Haha... Let me do the math on that.... mumble mumble... carry the 4.....?? Bazillions of words???

They sure are some long posts, but not one word more or less than is required to explain everything perfectly.

I will in due time post a few images with no info to up set the apple cart. Blackbox syndrome where you cant see anything going on inside isn't much fun.

Originally Posted by Peter Ward

Commendable processing effort Jase, though I too suggest the seeing has not helped the data. The image lacks a little colour or "punch" (sorry hard to quantify) for my taste. Interestingly, the background shows no colour noise at all

I've found nights that allow any 12" or larger scope to truly perform are rare indeed. None-the-less beautifully round stars, at over 3 metres FL, is no small feat.

Thanks Peter. Good feedback and similar to Mike's colour comments, I've "attempted" to address them in the revised rendition. Indeed, seeing can be a hit or miss affair - one of the challenges of deep space imaging. There's no freezing the seeing with glorified webcam on a 20 minute sub exposure. Though Lucky imaging may start making greater inroads. Thanks again for your comments.

Originally Posted by strongmanmike

Ok Ok ...I had another good look Jase and expensive scope time aside, it is a very nice image. The three main galaxies are pretty small I guess and it is a very small field, so yep...not bad

First impressions are important though...your Crab was really good

Mike
trying not to sound like a stick in the mud

Sorry Mike, the damage is done. You're not my friend any more.
NGC7582 - 5.0 x 2.3
NGC7599 - 4.4 x 1.4
NGC7590 - 2.6 x 1.0
Yeah, pretty small - requires focal length if you want details.
"Narrowfield rules" (c) Fred.

Originally Posted by Jen

beautiful pic Jase i would be happy to be able to see these in my scope let alone be able to take a pic of it nice work

Thanks for checking it out Jen! Pleased you liked it.

[Dennis]

Originally Posted by strongmanmike

Boy, great Dennis I feel like a right nitt picking woser now .....Hopefully Jase won't take me too seriously?
Mike

Hey Mike

You are one of Australia’s most talented in the astro photography department, not to mention the strongest astronomer ever to walk the planet, so I think your ability to analyse an image against technical criteria and provide suitable comment is several notches above my current capabilities, so I wouldn’t worry!

Cheers

Dennis

[multiweb (Marc)]

Great picture Jase, as always . Consistancy 's got to be your middle name. I like the colours a lot too. I can't really comment on anything else because having never gone that deep I don't even know the first thing about how challenging it must be to track and image at these long FL. But looking at the picture details and sharpness compared to the widefields I've been playing with to date I have a gut feeling it must be pretty hard and I think it's quite amazing how tight your stars are and how much details you got in the galaxy cores.

[atalas]

Nice image Jase...the focus looks soft to me.

[jase (Jason)]

Originally Posted by multiweb

Great picture Jase, as always . Consistancy 's got to be your middle name. I like the colours a lot too. I can't really comment on anything else because having never gone that deep I don't even know the first thing about how challenging it must be to track and image at these long FL. But looking at the picture details and sharpness compared to the widefields I've been playing with to date I have a gut feeling it must be pretty hard and I think it's quite amazing how tight your stars are and how much details you got in the galaxy cores.

Cheers Marc. Processing can work its wonders on mediocre data, of course it has its limits. Deconvolution is the main driver behind the tight stars and rich details. Oversampled data and deconvolution go hand in hand. Widefields with a high arcsec/pixel combination are generally not suited to deconvolution. You can use it, but results are sketchy. Thanks again!

Originally Posted by atalas

Nice image Jase...the focus looks soft to me.

Thanks Louie. Perhaps soft, but it wasn't due to focus. At least not when using computer controlled focusing with FocusMax. The CFZ is nailed everytime. If anything, the softness you report is likely to be seeing related. Thanks for check it out and making comment.

[Craig_L]

Wonderful image Jase. Don't know whether I will have any luck even registering them with a 400 FL but will give it ago.

[Garyh]

Well it is a very nice rendition of the Grus group thou the framing looks a little unusual to me. Other than that it is a very fine image
I bet you wished you had some great seeing but to fully utilize that focal length!
cheers Gary

[rogerg (Roger)]

Nice image Jase, great processing I like the colour, like the overall image, but feel it's a bit soft looking for my tastes, I'm tempted to see it sharpened but know it'd likely wreck it

The thing that surprises me most though is that he managed to get that much data in Pingerley... the weather here in south-west WA has been so shocking for so long it seems...

Roger.

[RB (Andrew)]

Jase, excellent capture !
The hi-res version is fantastic.
Not much I can add to this except I love the image.

[strongmanmike (Michael)]

Yes the colour in teh latest version is deffinitely better, slightly more resolution too, excellent

Mike

[Bassnut (Fred)]

Wow Jase, what a breath of fresh air

Some "strong" () critisism there, jealousy methinks , dont care about the gear, the processing is masterfull. The galaxies just pop out of the screen, and sooo smooth.

Nice change, a pleasure to view.