Rcw96-97-98

[jase]

Hi All,

Here's a rather cool grouping of emission nebulae in the constellation of Norma. RCW96, RCW97 and RCW98, with the latter probably being the most popular and commonly referred to as the Coffee Bean nebula.

RCW96, RCW97 and RCW98 (http://cosmicphotos.com/gallery/image.php?fld_image_id=283&fld_album_id=11)

Processed in CCDStack, MaximDL and Photoshop. Usual Ha+R blend in MaximDL using pixel math. When I saw blue reflection nebulosity in RCW98 (Coffee Bean) present, I thought I'd acquire some OIII data to see if there were other features of interest alas there is no other OIII in the area. OIII was introduced using a clipping mask for RCW98. Enjoyed processing the rich star field, bit of fun. Still refining a technique to managing star colours but so far results look ok. Not the flattest of fields. I believe this will be my last image with the Alta F16000. I may have a few other data sets with this camera but they are incomplete. Future images will be from the Aspen 16070 which has come back from repair and installed. More on that later.

Hope you enjoy it. :)

[Peter Ward]

Nice one Jase.

I'd like to see a tighter crop of the individual nebulae, but very tidy field just the same

(I'm also staggered 50 people looked but didn't take the time to comment...)

[gregbradley]

Good work Jase.

The stars are nicely protected and good shapes. Your coloration of the stars is probably correct, being quite pastel, but just my personal taste I prefer a bit more colour in them. It would make an interesting thread about what level of colour the stars should really be as the digital age has made it all too easy to manipulate colour.

Looking forward to your 16070 images. I imagine you will get much more depth and luminosity in your images from that sensor which I think is the next best thing after the 16803 and with the slightly smaller pixels better suited to your 16/F3.44 rig.

Greg.

[topheart]

Excellent work as always Jase!

Very nice combo of objects. Looking forward to your data with the new gear.
Cheers,
Tim

[leon]

Wow what a beauty Jase, love it

Leon

[jase]

Cheers Peter. :) I did contemplate the image composition along with crop. I liked the bright star cloud wandering through to the frame so a tighter crop may not have conveyed this. There are a few other interesting features further left of the frame too.

Not sure about the comments. Posting at night you often see a large number of guests online. Perhaps lurkers with no account or my images are too intimidating for some to comment. :lol:;)



Thanks Greg. :) Yes, we could debate star colours for sometime. The fast the f-ratio the harder it becomes as you're aware. For reference, all my RGB subs are 240s each with the KAI-16000 chip. I found 300s too high. The KAI-16070 will no doubt be different. I have a couple of subs of M83 taken unfiltered i.e. not through a lum filter and even moderately sized stars hit 65k in 240s subs with the KAI-16070. Filtered will not be an issue I suspect. I'm still doing 900s to 1200s subs at F/3.5 for narrowband subs to suck in the super faint stuff. I don't get saturated stars with narrowband data even at that sub exposure length. Still some more tuning to do with the optical train changes for the Aspen camera but will release something soon, perhaps of a mainstream object for a change to make it easier to compare with other images. Thanks again for the input.



Thanks Tim! Pleased you liked it. :) If you are looking to do any collaborative imaging again, like we did with IC1283-4 (http://cosmicphotos.com/gallery/image.php?fld_image_id=242&fld_album_id=11), just let me know. I'm always up for long focal length mosaic processing challenges! Once I get this set up bug free, I'll embark on some mosaic work.



Cheers Leon! :) Great to hear from you. Thanks for checking out the image and making comment.

[strongmanmike]

Cool trio of nebs Jase and nicely processed too nice and crisp...oh and yeah, I was certainly intimidated :scared: took me bloody ages to get up the courage to say anything :scared2:

Mike :D

[theodog]

I'm now too intimidated to NOT say anything.:scared:

Nice one Jase.
Is there any of the "Coffee Bean" close-up?

[topheart]

Thanks Tim! Pleased you liked it. If you are looking to do any collaborative imaging again, like we did with IC1283-4, just let me know. I'm always up for long focal length mosaic processing challenges! Once I get this set up bug free, I'll embark on some mosaic work.

Sure Jase, contact me off-line and we can discuss - plan a project if you like.
Cheers,
Tim

[Rex]

Top shot Jase! So many stars, good detail and great framing. Loving that double at top centre, adds a little extra pizzazz.

[astronobob]

Mighty nice image Jase, bit of everything in there, dig the colors and field, sharp and dusty :thumbsup: :thumbsup:
Job well done :thumbsup:

[Paul Haese]

Excellent field Jase. Lovely variations in colour. I particularly like the pinkish tint to the coffee bean when compared to the other nebulae. I like the star colour too: from a spectral position those look just about right. David would certainly think so I would imagine. There appears to be some dark rings around the stars within the nebulae which might need some correction. In any event something out of the ordinary and nice to gaze at for a while. Thanks for posting another different field.

[jase]

Haha! Cheers Mike. :) You...intimidated...hahah. Nah! :lol:;) Yeah, its a interesting field. The constellation of Norma has a few more gems like this. May visit a few more from the constellation this season, time pending. Though will likely need to wait.



Thanks Jeff.:) Pleased you liked it. You'll find a couple of close up images of the Coffee Bean neb on the web. I personally like the wider field images of this area such as the one from our very own Steve Crouch here (http://members.pcug.org.au/%7Estevec/rcw98_STL11K_FSQ106.htm). Thanks for checking it out and making comment :thumbsup:



I will certainly take you up on the offer Tim, thanks! Have a few targets in mind but I'll need to get your updated TSX FoV and OAG offset before I can start planning in photoshop. Will try keep the position angle similar to reduce the workload like we did last time. Will ping you an email shortly :thumbsup:



Cheers Rex! :) Indeed, I enjoyed checking the double at top center too. Looks like I've only just split it. The angular resolution with this set up works well at around 1.1 arcsec/pixel. No doubt aperture helps, as do the pristine skies at SSO noted in a study found here (http://inspirehep.net/record/1190821). Every little bit helps!



Thanks Bob! :) Agree, the field is rather diverse with varying colours and features. My favorite part isn't the nebs but the star cloud structure and tones. Thanks for checking it out :thumbsup:



Cheers Paul! :) Star colours are certainly subjective. I don't use the star colours from a Ha+RGB blend alone as I find there is normally a colour shift due to the Ha. Base RGB stars are best. The rings you note around stars in the nebs are not due to sharpening. I don't use deconvolution with data from this system. Sampling is ample and with so many stars in the field deconvolution often mottles the background. I suspect what you are seeing is the stellar profile itself. On closer inspection, you'll probably find the ring is in fact colored which further confirms its the stellar profile not a processing artefact. Bringing in the RGB stars in lighten mode on a [Ha+R]GB blend can sometimes show what appears to be a star ringing effect. Its not often a smooth transition between star and neb occurs. Altering the RGB layer opacity can sometimes work. You've given me some ideas though. A star mask with a mild blur may soften the transition. I think this would need to be applied in two or three layers as the first mask would likely be a global change impacting the entire image so an iterative approach would be needed. May consider investigating this next time. Not going back for a repro on this one! Thanks for the great feedback. :thumbsup:

[AG Hybrid]

Nice work. Busy field you have there.

[Paul Haese]

Definitely star profile related and was not suggesting it was decon related. The star profile of the Ha is a lot smaller than the RGB star set. I have seen this before myself with some of my images. I found that doing a final RGB wash as you suggest with either lighten mode or screen mode works best to remove the problem. Looking forward to your next image. :)

[multiweb]

That's a nice shot Jase. :thumbsup: How is your ASA modified?

[jase]

Thanks Adrian! :) Pleased you liked it.



Cheers Paul. :) Yes, Ha data sets typically have stellar profiles which are smaller. The Ha was only added to the red filtered data which has a larger stellar profile structure. So doubt this was the cause. I'm not using Ha as luminance which would certainly exacerbate any form of ringing. I'm thinking there is a better way of introducing RGB stars back in than just lighten mode alone. I have a few other ideas I will try. Still working through a few optical train bugs, but hopefully will release another image shortly. Thanks again for the feedback.



Thanks Marc! :thumbsup: Pleased you enjoyed it. Modification include a more rigid carbon fiber tube made by Public Missiles, 16" primary mirror refiguring, coating and addition of a mirror cell sling to provide improved support for the primary were done by Optical Mechanics Inc (OMI). Other components are ASA original including the OK3Z focuser and Wynne corrector, which I would argue is the best corrector on the market for newt astrographs. Keller knows his optics. The new tube is a different carbon fiber composite to the original and slightly thicker which results in a really snug fit with the mirror cell. PIA to remove and refit for mirror cleaning but hopefully wont need to do it too often.

[strongmanmike]

Nothing dark or serious, I'm just interested in how you have come to that conclusion Jase? Or are you just referring to the general design of a Wynne corrector?

Mike

[jase]

Mike, I work on the simple principle the less glass light has to travel through the better. Why have 4 or 5 elements when you can get the job done in 3 is perhaps the question that needs to be answered.

[strongmanmike]

Hmm? Interesting...let's compare a Plossl to a Nagler for instance, which is the "better" eyepiece :question:

Mike

[jase]

We are talking correctors not eyepieces. If you want to talk eyepieces, probably best not post in a deep sky imaging forum. :lol::P

[strongmanmike]

Oh no, whaaa :sad: can't we just have a meaningless my corrector is better than your corrector intellectual argument for the sake of it :sadeyes: sniff....

Actually, I am getting into eyepieces lately too, about to buy a 24mm Panoptic :D..has quite a few glass elements though :scared: ;)

Mike

[RickS]

Another off-the-beaten-track image. Nicely done, Jase!