IC4633 in Apus w/IFN

[jase (Jason)]

Hi All,
I’ve been sitting on this image for sometime and believe now would be an appropriate time to release it. I produced this image exclusively for Lightbuckets to display at the AIC2008 conference which is presently being held in San Jose, California. I was looking for something rather unique and intriguing. So without further ado, I’m pleased to present IC4633 in Apus.

About the target;
IC4633 is a spiral galaxy (Sc type, mag. 13) located in the constellation Apus. The galaxy is almost obscured by a vast and very faint interstellar nebulosity known as Integrated Flux Nebulae (IFN). This type of nebulae is illuminated not by a single star, but the energy from the integrated flux of all stars in the Milky Way. The nebula consists of hydrogen, dust particles, carbon monoxide amongst other elements and has been designated MW9.

Some words on the image;
Something for those that like targets off the beaten track. The image is an LLRGB composite with a total exposure time of 9 hours (L:280min,R:90min,G:80min,B:90min). It was acquired using Lightbucket’s 14.5” RC (~3315mm FL) located in Pingelly, WA. Despite the ample planning, dark skies and instrument utilised, I really had a hard time with this image. At Pingelly, IC4633 crosses the meridian at 44.5 degrees which made obtaining good resolution difficult – the further south you’re located, the better. This took additional planning where I only acquired the luminance data over successive nights when the object was at the highest point. I feel the stars reflect the lack of resolution, considering they appear rather soft...in some cases looks like a guiding issue, even though there wasn't one! The luminance data was combined using Sigma Reject in MaximDL and placed through two iterations of deconvolution using CCDSharp. The IFN is faint, so realised it needed to be stretched reasonably hard to extract it’s wispy features. Having played around with curves to stretch the data, I was not obtaining the desired result. I used DDP, something I don’t often do to achieve the task, and ensuring no data was clipped in the process. The reasoning behind the DDP decision was also the management of stellar profiles in one-step. I duplicated the original luminance frame and stretch it using conventional level and curves to a point where the galaxies showed good structure with no clipping. Selective processing through PS layers was invoked to combine the two. Subtle intensity differences between the layers were addressed with PS brighten/contrast control. Layers were flattened and relayered again with RGB data to manage detail and colour saturation. Talking RGB data, I struggled with getting it looking “correct”. While the flats applied were correct for the PIR angle, I experienced colour shifts between the filtered exposures, perhaps due to the low altitude. This resulted in mottling which is visible in the presented image. While I’ve chased this effect before in other images using a Gaussian blur mask, I found it too much of a tedious job when dealing with a background that isn’t uniformly dark due to the IFN. There maybe other ways of dealing with the issue, but I have yet to come across one which is effective. I reduced the impact of the mottling with a low frequency invert mask created in noise reduction PS plug-in Neatimage with a reduced fill effect, blended as colour. Not ideal, but worked ok. Always willing to try something different to see if the step leads to improvements. Being low in the sky (even at its highest point), the blue channel could have done with considerably more data to compensate for atmospheric extinction. I did however apply a multiplication factor which appeared to restore the weight, be it subtly. The dusty characteristics of the IFN are perhaps too colour saturated, but think the effect works well with the contrasting blue hue of the spiral galaxy. This is a fascinating region in which I’ve previously targeted with the FSQ, but have insufficient data to work with. Maybe next season, I’ll complete the mission if not distracted to move down the target list for the season in the meantime.

I’d like to thank Steve of Lightbuckets for providing the opportunity to nail this target and permission to post on the website.

Thanks for checking it out, hope you like it. As always, all comments welcome.

Cheers

[RB (Andrew)]

Shame about the cloud, couldn't you wait till a clear night Jase ?

[multiweb (Marc)]

That's a beautiful image. Very very nice! Have a great time at the conference.

[jase (Jason)]

Originally Posted by RB

Shame about the cloud, couldn't you wait till a clear night Jase ?

, this cloud caused me no end of headaches - as one can tell by my rambling on. Anyway, I had fun putting it together despite some of its short falls. Cheers RB.

Originally Posted by multiweb

That's a beautiful image. Very very nice! Have a great time at the conference.

Thanks Marc. Rather interesting target - something different from the mainstream objects. Will try provide more updates. Thanks again.

[xelasnave]

Inspirational Jase that is impressive.
alex

[atalas]

Hi Jase

No point in talking about the stellar profiles cause you've covered all your issues anyway dude !

It's still a wonderful image well composed and the detail is very good and I absolutely love the dust !!

[RB (Andrew)]

Originally Posted by jase

, this cloud caused me no end of headaches - as one can tell by my rambling on. Anyway, I had fun putting it together despite some of its short falls. Cheers RB.

Mate ! I'm just gobsmacked at this image, it's 'simply' an unbelievable 'scene', brought to 'life' by your imaging expertise and wonderful equipment available at Lightbuckets.
Thanks for sharing not only the image but also the background info and the techniques you used.

Cheers mate.

[h0ughy (David)]

who spilt the coffee on the negative Jase? well i liked Mr sidonio's C4 - this is just as special with the cosmic dust!

[Kevnool (Kev)]

inspirational stuff...cheers Kev.

[strongmanmike (Michael)]

This is indeed a very interesting and often overlooked region of our south pole area. I like your handling of the subject, particularly given the less than perfect conditions, you did have a pretty special rig though . On an image processing front and only a minor observation, it does look slightly too smoothed to me and soft but I know you like'em this way and you know how I stand on that "noisey" issue plus I know your conditions were less than optimal too, still looks great.

It was an image of this area by Jim Rifle that caused me to seriously look at investing in one of those amazing Centurion 18 scopes a couple of years ago but I decided it was too expensive and went with the more affordable ASA N12..?...

You probably perused it in your image history study on this region but here is Jim Rifles shot of the same region:

http://astroworks.com/gallery/ST2000GAL/ic4633.html

Not quite as good as yours or Jims version but I imaged the same region a couple of years ago too with a little 80ED and my trusty little SXVH9:

http://www.pbase.com/strongmanmike20...74684/original

and (somewhat poorly) with a 135mm camera lens:

http://www.pbase.com/strongmanmike20...16974/original

Nice work Jase

Mike

[Octane (Humayun)]

Jase,

Wonderful. Just wonderful.

I had a look at the pricing on Lightbuckets. My goodness, for a /decent/ image, you're up for close to a thousand dollars. Insane.

Regards,
Humayun

[Peter Ward]

Don't know Jase....the choice of telescope may have been a bit dodgy...
(damm those Pingelly skies)

Nicely processed just the same

[jase (Jason)]

Originally Posted by xelasnave

Inspirational Jase that is impressive.
alex

Thanks Alex. Pleased you like it.

Originally Posted by atalas

Hi Jase

No point in talking about the stellar profiles cause you've covered all your issues anyway dude !

It's still a wonderful image well composed and the detail is very good and I absolutely love the dust !!

Cheers Louie. Nah, stellar profiles are still important. "Crunchy" stars aren't appealing. The IFN does add an element to the scene.

Originally Posted by RB

Mate ! I'm just gobsmacked at this image, it's 'simply' an unbelievable 'scene', brought to 'life' by your imaging expertise and wonderful equipment available at Lightbuckets.
Thanks for sharing not only the image but also the background info and the techniques you used.

Cheers mate.

Thanks RB. This image certainly tested my sanity. Came out well in the end. The Lightbucket team is here at AIC so good to catch up. Great guys. Hope the background info on processing was of use or at least gave an insight into what went on.

Originally Posted by h0ughy

who spilt the coffee on the negative Jase? well i liked Mr sidonio's C4 - this is just as special with the cosmic dust!

Cheers Houghy. Sidonio's C4 is still one of my favs, but this region needs more attention from others to do it justice.

Originally Posted by Kevnool

inspirational stuff...cheers Kev.

Thanks Kev!

Originally Posted by strongmanmike

This is indeed a very interesting and often overlooked region of our south pole area. I like your handling of the subject, particularly given the less than perfect conditions, you did have a pretty special rig though . On an image processing front and only a minor observation, it does look slightly too smoothed to me and soft but I know you like'em this way and you know how I stand on that "noisey" issue plus I know your conditions were less than optimal too, still looks great.

It was an image of this area by Jim Rifle that caused me to seriously look at investing in one of those amazing Centurion 18 scopes a couple of years ago but I decided it was too expensive and went with the more affordable ASA N12..?...

You probably perused it in your image history study on this region but here is Jim Rifles shot of the same region:

http://astroworks.com/gallery/ST2000GAL/ic4633.html

Not quite as good as yours or Jims version but I imaged the same region a couple of years ago too with a little 80ED and my trusty little SXVH9:

http://www.pbase.com/strongmanmike20...74684/original

and (somewhat poorly) with a 135mm camera lens:

http://www.pbase.com/strongmanmike20...16974/original

Nice work Jase

Mike

Thanks Mike. Yes, I check out Jim's version in the planning. I spent quite some time determining the FOV/framing of this target. Excellent work with the 135mm lens. I've covered a similar FOV with the FSQ, but its a two frame mosaic - which needs much more data before I can take the image to the next level. Yes, a little too smooth for your liking - I can understand that. Its on the border line for me too, but found it difficult to handle the mottling hence the smoothness. Thanks again for your comments.

Originally Posted by Octane

Jase,

Wonderful. Just wonderful.

I had a look at the pricing on Lightbuckets. My goodness, for a /decent/ image, you're up for close to a thousand dollars. Insane.

Regards,
Humayun

Cheers Humayun. It can get expensive, but you need to be smart. Full moon means discounts - so I nail as much Ha data as I can over these periods. Pleased you like the image.

Originally Posted by Peter Ward

Don't know Jase....the choice of telescope may have been a bit dodgy...
(damm those Pingelly skies)

Nicely processed just the same

Thanks Peter. Yes, a wide field scope would suit the scene, alas no resolution on IC4633 so its a trade off.

=======

Thanks again to those how made comment. Much appreciated.

[Hagar (Doug)]

Very nice image. Interesting target and a not too often imaged area. Your processing skills definitely show out in this image given the conditions. I wish I could manage some of the methods you use. Maybe one day.

Great stuff Jase.

[Peter Ward]

Originally Posted by jase

Thanks Peter. Yes, a wide field scope would suit the scene, alas no resolution on IC4633 so its a trade off.

Jase, Jase, Jase..... who in their right mind would use a RCOS 14 ? I mean really? (....just joking )

[sjastro]

Excellent Jase.

Haven't seen that one before.

Steven

[jase (Jason)]

Originally Posted by Hagar

Very nice image. Interesting target and a not too often imaged area. Your processing skills definitely show out in this image given the conditions. I wish I could manage some of the methods you use. Maybe one day.

Great stuff Jase.

Thanks Doug. Others should give it a go. It does present some challenges, but that's what imaging is all about right. Never be afraid to try something different in your processing as you'll learn from the mistakes.

Originally Posted by Peter Ward

Jase, Jase, Jase..... who in their right mind would use a RCOS 14 ? I mean really? (....just joking )

True, especially when something better is available. Talking to some folks... give it a year and I expect we'll see a 24" RCOS rental scope (or at least a 20") become available in Oz. Maybe its time to get the 14" out of the burbs and into a dark sky site...start unleashing the power. If you can't beat'em, join'em.

Originally Posted by sjastro

Excellent Jase.

Haven't seen that one before.

Steven

Thanks Steven.

[Garyh]

Very pleasing image Jase!.. I don`t ever recall seeing a image of this area before so thanks for the enlightenment!
The distant galaxies with the interstellar dust make such a beautiful contrasting image. Nicely composed as well. Pitty the seeing/weather was not on your side but you still pulled the rabbit out the hat for sure!
cheers Gary

[gregbradley]

Fabulously impressive image Jase.

You are a master at this art.

That object is new to me and its on the list now. Cheers mate.

Greg.

[bluescope]

Nice to see you imaging from our Western skies Jase ... two weeks to go 'till I move to my dark sky dwelling ... dismantled my observatory on the weekend ready to go. I'm not familiar with this target so I'll have to check whether I can see it from my place ... looks very interesting !
Nice work as usual !