Antlia cluster (part of)

[Shiraz]

Hi

This bit of Abell S0636 is a beautiful cluster with two major (and similar) ellipticals apparently attracting a varied range of smaller galaxies. The scene appears to have a slight, misty local reflection nebula, apparently illuminated by the bright foreground star cluster and presumably also by integrated flux from elsewhere. There is also a little background redness in places, about where Rolf identified a weak SN remnant. Also, if you toggle to full res, there is a spatter of tiny pale orange dots at about 8 o'clock to the rightmost big elliptical - looks to be a background galaxy cluster at a vastly greater distance.


antlia cluster (http://astrob.in/full/247276/None/) (you can toggle to full res in top right corner of the page)

I arranged the composition based on the galaxies, but it has been thrown out of harmony by the reflection nebula - which wasn't readily visible until I stacked. Oh well, this is what it is:).

if interested, lum 177x300s 1x1, R 67x180s 2x2, G 30x180s 2x2, B 50x300s 2x2. Minimal processing (colour balance on foreground stars, deconvolution, stretching, slight colour tweak)

thanks for looking. regards Ray

[codemonkey]

Awesome work Ray! Love the composition, you picked the most aesthetically pleasing part of this cluster and framed it very well.

Kinda wishing I'd put a few more hours into my effort after seeing this. I didn't even notice the reflection neb/IFN in mine.

Is this a crop? What are you sampling at ("/px)?

[Shiraz]

Thanks very much Lee. This is trimmed around the edges, but is almost the full frame at 0.91"/pix

[Placidus]

Looks like a galaxy cluster seen through the Pleiades.

Ray, you are getting seriously good at these.

Best,
Mike

[gregbradley]

That's a wow image. When you first look at it you go "Wow".

Impressive.

Greg.

[Rick Parrott]

:eyepop:Just a beaut shot!

[Atmos]

That's amazing Ray, can certainly understand how you wouldn't have spotted that nebula until after stacking. Looks seriously faint!

[strongmanmike]

What an interesting image Ray, I had a great time surfing and yes that distant galaxy cluster is super cool.

Great work, really enjoyed the view :thumbsup:

One thing, how have you determined that that blue glow is reflection neb?

Mike

[Shiraz]

thanks very much Mike - I appreciate your comment. Yes. it does look a bit like the Pleiades :)


well thanks Greg - that means a lot.


thank you Rick!


Yes Colin, it is very faint, but it is definitely there.


Thanks a lot Mike. I guess that the diffuse glow could either be dim reflection nebula or galactic cirrus. Since it seems to be moderately well correlated with the bright stars in the cluster and even appears to take on a little of their colour, I concluded that it was probably local reflection nebula (as Mike pointed out, it looks a bit like the Pleiades). However, it could well be much deeper galactic cirrus and the local scattering could be in my scope - I have no way of knowing and would welcome opinions.

regards Ray

[strongmanmike]

Does it show in Rolfs?

[Paul Haese]

An interesting field of view Ray. I found the comparisons between your image and Rolf's in terms of what looks like cirrus to be fairly similar.
I think the whole image looks a little blue/magenta to me and the orange stars appear a little muted. That is a minor consideration when you take the time to consider the depth of the image. There appears to be literally thousands of galaxies in the field both near and far, some clearly red shifted quite a lot and those being tiny fuzzy specks. Thanks for posting Ray.

[RickS]

That's a wonderful collection of fuzzies, Ray, and the faint neb is the icing on the cake :thumbsup:

Cheers,
Rick.

[Flugel88]

Wow the Galaxies seem to outnumber the stars.
Lovely image very crisp.

[topheart]

Excellent Ray!
Cheers,
Tim

[graham.hobart]

Just magnificent Ray.
A eye popper!!
Graham :thumbsup:

[Andy01]

Pick a galaxy, any galaxy!
Very nice work Ray, well done :)

[Shiraz]

no. however, there is a background in the DSS1 image that has roughly the same structure - attached image shows the DSS1 image and the low spatial frequency background that was extracted. My image has bright and dark bits in pretty much the same places and also shows a gradation in background, increasing towards the lower right corner.

I don't have the depth to get down to the fine structure that Rolf's wonderful image shows, but I tried a bit of enhancement and got generally similar line features and swirls etc. Not worth posting because I did a rough processing job on the stretched image and ended up with a lot of noise.

I guess the main question is whether the low spatial frequency structure is real and if its is, what it could be. I am still not sure, but originally left it in because I have never previously recorded any gradients that distinct (except when my mirrors once got coated in sea mist). Will have a close look at the optics and carefully inspect the subs - and if it turns out that I have a red herring, will reprocess - thanks very much for your help so far:thumbsup:.


Thanks very much Paul - I will go back and have another look at the colour. Yep, the density of galaxies in this area is astonishing.


Thanks very much Rick!



Thanks very much Michael - yes there are lots of galaxies:)


Hi Tim. Thanks very much


Thank you Graham - appreciated.


Hi Andy. yes, there are a few:)

[strongmanmike]

Yep, looks close enough to me too :)...nice work Ray, comparing to pro results is often very useful (regardless of what some people think ;)) for varifying features and details and helping to rule processing artifacts out or real features in :thumbsup:

Mike

[Shiraz]

I think that it is still a "maybe" - wouldn't bet a sheep station on it just yet :lol:

This effect could be dirty optics (cleaned just recently though), fine dew on the mirrors, high altitude ice or cirrus clouds, spider's web in the OTA, smoke from neighbours' fires, stray light leakage etc. etc.

[Stevec35]

Most impressive Ray - a fine effort!

Cheers

Steve

[Shiraz]

Thank you Steve, much appreciated. regards ray

[rustigsmed]

spectacular stuff Ray what a brilliant part of the sky!

[SkyViking]

Ah the good ol' Antlia Cluster, wonderful to see another image of it, and a fine one for sure Ray! In total there must exist upwards of a staggering handful of images of this cluster now, it's almost becoming mainstream lol :D
That faint reflection nebula looks interesting. Being such a large scale gradient I certainly can't deny that in my version it could have succumbed to the process of bringing out the smaller scale IcL and IFN structures.
As for the distant background cluster, yes there in fact indeed many of those all over the FOV. They look awesome seen though the main cluster - really puts the distances into perspective.

[deeplook]

Very nice and deep image Ray! Looks spectacular to me, perfect.

Markus

[Shiraz]

Thanks Russell. you are right, it is a beaut part of the sky.


Thanks very much Rolf. Nothing like as deep as your magnificent image, but it was still rewarding to see so many galaxies.

I am still not completely convinced that the large scale nebulosity is real - have been going over the processing again today and have not yet found any issues, but I need to redo the bias, to make sure there is no drift there. Even the slightest offset or bias error can show up when going this deep. I had cleaned the mirrors in preparation for this target, so that should have been OK - mind you they have picked up a lot of dirt since then.


Thanks very much Markus - appreciated

regards ray

[Rex]

Wow! What a fantastic image Ray. I could swim around in that all day and still not see it all.

[Shiraz]

Thanks Rex. Glad you enjoyed it - appreciate the comments.

[multiweb]

Very crowded field. Love the highres. Lots to see. :thumbsup::thumbsup::thumbsup:

[clive milne]

Excellent shot Ray...

I'm not sure whether this is good news or bad news, but you have your system operating at a level where the limit appears to be lateral charge diffusion.

Incidentally ... did you mask (the bright stars) for decon?

[DavidU]

Fantastic image Ray :thumbsup:

[Shiraz]

Thanks Marc. there sure are lots of galaxies out there - real thrill to see them appear out of the noise.


Hi Clive. I have been thinking about the need for finer sampling - it seems that my original design assumption of 2 arcsec as the best possible seeing was a bit pessimistic. Oh well, not a bad problem to have I guess. FWIW, the biggest gain in seeing came from putting the scope in a temperature controlled ROR observatory.

For this image, very little deconvolution was needed, since the original stack was about 2.2arcsec FWHM. I don't do any masking for deconvolution on the basis that the original convolution I am trying to wind back was a global process - and the PixInsight deconvolution process has effective clamping to minimise ringing on saturated stars. However, am open to alternative ideas.


thanks Dave - appreciated.