NGC 6188 - Ara Shoreline (reprocessed)

[Placidus]

Another go at part of NGC 6188. No dragons from this close (FOV 36'arc) but instantly recognizable. Hubble palette with whitened stars.

Red: SII 7hrs; Green: Ha 4hrs; Blue OIII 7hrs. More time was allocated to the fainter channels in order to reduce noise.

Things we love about this part of the sky:

- Looks like a coastline, with a big blue lake on the left, land on the right, and a craggy, corrugated cliff of shoreline in between.

- Amazing series of rings in OIII presumably blown by stars related to the cluster in the middle of the lake. So many interlocking bubbles as to almost make a froth.

- The coastline includes a large black and ginger cat sneaking vertically downward. A single bright star forms the cat's eye, about 75% of the way down the page. The cat's two ears, pricked up, are very obvious. It's thoughts are of mouse and apple pie.

- Above the cat, and coincident with the cat's tail, is a rocking horse. There are many fine, sharply demarcated pillars, wisps, and tendrils sticking out of the shoreline.

- The rest of the image is awash with faint sharp traceries, much more obvious in the original image (www.photos.smugmug.com/Category/Star-Forming-Regions/i-h2wxwB2/0/O/Ara%20Shoreline%20Ha%204%20OIII%207 %20SII%207hrs.jpg) that makes one think of ancient ruins.

EDIT: Here is a Revised Link (www.photos.smugmug.com/Category/Star-Forming-Regions/i-8SNsVnz/0/O/Ara%20Shoreline%20Ha%204%20OIII%207 %20SII%207hrs%20Revised.jpg) revised version after much discussion of artefacts round stars and green blobs.

Minimal processing, all done using our GoodLook 64 suite.

Chewed through some generator fuel taking this set over a couple nights. After 100 mm of rain in ten days (and 80 tonnes of fresh drinking water in our new rainwater tank), condensation had gotten onto the computer-controlled remote "generator off" board, so it had to be disconnected, and the generator switched off by hand at a civilized time in the morning when the temperature had risen above zero. Fred Vanderhaven visited, and gave some useful advice on making the board a bit more resilient. All implemented now.

[graham.hobart]

One of my favourite areas of the Sky and I like your presentation. Very sharp folks!
Graz:thumbsup:

[RickS]

Excellent detail as always, M&T, and I like the more traditional colouring. Well done!

Cheers,
Rick.

[strongmanmike]

Ha ha yes, I see your cat and rocking horse. The rocking horse has always reminded me of a big set of fluffy dogs ears (when turned clockwise 90 deg) perhaps a Border Collie? :) A few processing artefacts visible (need to talk to the software designers :whistle:) but no denying the fine detail in the nebulosity and the pleasing colour palette too :thumbsup:

Mike

[Placidus]

Thanks, Graz. Delighted by your comments.



Hi, Rick. Many thanks. As Mike S mentioned, the star-whitening process and masking the stars when sharpening have both left some artifacts, but we're pleased with the nebulosity.



Thanks Mike. You are absolutely right about the Collie's ears. They're convincing and almost to scale with the cat. Perhaps those aren't really artifacts around the cluster stars - I'm sure I can see them with my ageing naked eye! :lol:

[gregbradley]

A wonderful image Mike. I like this a lot. I have never seen those rings in the O111 before. A great find. I'll have to go looking for them now!

Greg.

[RobF]

Excellent pic. Thanks for sharing with us.

[Atmos]

Really nice shot MnT, the detail is wonderful, especially those OIII bubbles! So many animals in these images that i don't see unless they're pointed out to me :P Entertaining with what you two and Michael spot out there in the vastness of space :lol:
I'll have to find out what patch of sky this is in, see whether I can actually image it from where I am house sitting at the moment.

I have spent many many hours figuring out how to fiddle with stars without creating ringing artefacts, getting better but still quite a ways off how I want my stars to look :P

[Andy01]

Hi M&T, nice work on this Ara closeup.
I get the shoreline reference, and I can see the cat- can't spot the rocking horse though, it's like playing "Where's Wally" looking at your images :)
Great detail & the colours look pleasing.
Nice pickup with those O3 bubbles too :)
Cheers
Andy

[Placidus]

Thanks muchly Greg.




Cheers, Rob.



Thanks Colin! The beast is in north-western Ara, almost Scorpius. I wake at night trying to think up better ways of handling magenta stars. It's easy if they're against blackness. The problem is when they're against strongly coloured and textured nebulosity.




Hi, Andy, and thanks. As Strong Mike says, the rocking horse looks more like the ears of a Border Collie.

[Stevec35]

Nice one guys. Some interesting detail there that I haven't seen previously and I love the colour.

Cheers

Steve

[Placidus]

Thanks, Steve. Delighted.

If, in another life (far far away) we had lots of clear sky, we'd love to do the next panels north and south, and make a bit of a mosaic.

[Retrograde]

Looks great Mike and Trish - such exquisite detail.




Please, please do this (if you can) :D

[Placidus]

Thanks Pete! The mosaic is certainly on the to-do list, but the soggy weather continues. 33 mm in the last 24 hours.

[Paul Haese]

Hi MnT,

A huge image which shows some interesting detail and nice colour but there are a few warts that are spoiling the image in my opinion. There are many green dots scattered through out the field of view. They can mainly be seen in the blue areas. Also the reduction of the magenta halos has produced an odd looking halo around the bright stars. I wonder also whether you would consider doing some selective sharpening around the edge of the gas and dust regions. I feel it would make the image pop.

[marc4darkskies]

Great image M&T! Colours are wonderful! :thumbsup:

I agree with Paul though. It seems your treatment of magenta halos has left orphan rings around stars which are very distracting in the full res version.

[Atmos]

I have had similar results when doing star removal on the individual images before combination. The Ha having a LOT better SNR takes star reduction leaving virtually no detectably warts, OIII and SII on the other hand can be very sensitive.
This is my assumption, was done removal before RGB combination.

[Placidus]

Thanks colleagues. My problem is as usual colour-blindness. The pic looked fine to me. I swapped the red and green channels, and BLECCHARAMA! I can see what you are talking about. This is going to take some time to fix.

Very best,
Mick the Greek.

[Bassnut]

Its a very good pic Mike, I like it. Could you just feather the star selection algorithm?.

[Placidus]

Thanks, Fred! Urgently needed moral support.

Everyone:

I've reprocessed from scratch, with no important change to what I thought I was doing. I think it's come out much better. In particular, the green blobs have gone. No idea what went wrong before. Evil gremlins.

Here is the link to the revised version. (www.photos.smugmug.com/Category/Star-Forming-Regions/i-8SNsVnz/0/O/Ara%20Shoreline%20Ha%204%20OIII%207 %20SII%207hrs%20Revised.jpg)

[multiweb]

The repro is just superb Mike! Well done. :thumbsup::thumbsup::thumbsup:

[Atmos]

Excellent repo MnT, particularly like the new black point, makes the image far more contrasty :)

[Placidus]

Ah, you spotted the change in black point! Thanks, Colin!



Many thanks, Marc. Felt a bit sheepish when I noticed the artefacts. No idea how they got there. I think I used a mask to blend in the wrong image. Not paying attention. I blame the excitement of first use of a brand new computer with a 4K screen. Cheerier now.

[marc4darkskies]

Ah yes! Muuuuch better M&T!! Overall a superb image! :thumbsup::thumbsup:

My only other humble suggestion (agreeing with Paul H) is that the higher signal areas might benefit from some gentle sharpening.

[Placidus]

Thanks, Marcus. Will get out the pencil sharpener.

We're off to Dubbo zoo today. Last time it was high summer and 40 deg. Right now it is only 7 deg outside. The animals and ice creams will look different.

[gregbradley]

That's a nice improvement.
Greg

[Paul Haese]

Yep that looks much better MnT.

[Placidus]

Thanks guys. Mike will have to routinely swap the red and green channels and have another look before posting in future.