IC2118 – The WitchHead Nebula

[jase]

Double, double toil and trouble; Fire burn and cauldron bubble…

Hi All,
Might as well kick off my 2008 imaging series with an evil stature, so I’m pleased to present IC2118 – The WitchHead Nebula (http://cosmicphotos.com/gallery/image.php?fld_image_id=129&fld_album_id=11)

A sinister shaped figure known as the WitchHead Nebula (IC2118) resides in the constellation Eridanus. The nebula primarily glows due to the reflected light from the bright star Rigel located 2.6 degrees away in the constellation Orion (seen top right of frame). The blue hues are due to the dusty characteristics of the nebula as dust reflects blue light more efficiently than red light. This is in contrast to interstellar reddening phenomenon where dust suppresses blue light near the center of our Milky Way galaxy. The WitchHead Nebula resides approximately 1,000 light years away.

About the image;
Technically, this data was acquired last year, but it takes me a while to process an image spending many nights working the data over. The image is a BRGB composite totalling 5 hours (R:90 mins; G:90 mins; B:120 mins). image has been reduce and cropped for web appearance. One thing for sure is IC2118 is not a strong Ha target, in fact when I went through the raw subs of the individual RGB frames, it was the blue frame which displayed the most detail due to its dusty characteristics. I decided to do something different and use the blue channel as the luminance, though I suspect I would have had a better result in reducing noise in the dim areas performing the standard LRGB methodology. I think this would be a good target for unmodded DSLRs, though it’s not bright. In my composition I made Rigel a feature, thus included it into the frame (top right). I experienced many difficulties in processing this object. In particular Rigel - This is one really bright star at mag 0.18 which washed out all nebulosity and colour in its vicinity. The only way I could bring back the WitchHead was use numerous layer masks for both luminosity and colour management. Certainly the most masks I’ve had to create in an astroimage before (total of 8) and quite a processing challenge. I’m not happy with the background as it’s not flat and still exhibits some colour shifts when equalised. Stars just off the edge of the frame also created flares that protruded into the frame. Ok, enough of my bantering on – I’ve spent way, way too long processing this image. Need a break from it - time to get “dirty” with some quality telescope time acquiring data for three other imaging projects I’ve started, but appear to never finish.

Thanks for looking. Hope you enjoy!:)

Cheers

[sheeny]

Very nice Jase! I like the composition - looking at the star.

Al.

[Hagar]

Magnificent... Love your work!!!

[leon]

Jase That is some awesome image, were do you get all this celeverness from. (is there such a word) :whistle: i love it.

Leon :thumbsup:

[mick pinner]

that is a stunning image Jase love it.

[theodog]

Very nice image Jase. Would any more processing give value for time spent? -I think not. All that is required in an image is there in spades.:thumbsup:

[glenc]

Thanks Jase, another masterpiece.

[Matty P]

Outstanding image Jase, a true work of art.

[Rigel003]

Fantastic image with so much detail in the nebula. Beautiful composition too with the way you've framed it with Rigel.

[Alchemy]

i read the other replys first before checking out the image .... what can i say... ditto.:eyepop:

really nice jase , a quality start to the year.

[peter_4059]

Great image - love the way it appears to be looking at the star.

[browndog]

Agree with all of the comments so far. Really great image.
The detail in the nebula is fantastic, it really does look like a witch...

[jase]

Thanks Al. :) I did pay particular focus on the composition as I wanted to show what was causing the reflection. The version displayed is cropped. There is actually a little more space around the edges of the full frame which I'll use for prints etc. Composition was tight however and took quite some time to frame correctly (approx 30min or so). When I finally kicked of the imaging run, the auto guider wasn't tracking correctly, then I realised that because I rotated the FOV I need to recalibrate - Doh! It’s the simple things in the middle of the night that get you.



Cheers Doug, pleased you liked it.:thumbsup:



Thanks Leon.:thumbsup: I'm assuming you mean cleverness (or you've just invented a new profanity for the Websters dictionary);). Nothing special let me tell you. I simply do all my planning (target, location, composition, exposure times, framing, guide star selection, etc) well before I’m at the telescope. From the plans, I create scripts which I upload to the telescope – the rest is pretty much automated. Seriously though, never over look composition. If you’re looking to step up your imaging, take the time to frame the object with some thought – make it interesting and give depth. The FSQ you’ve got is a great instrument for object pairings. Try fitting a few objects in the FOV or perform a mosaic to get the result your after. You’re only limited by your imagination.



Thanks Mick. Appreciate the kind words.:thumbsup:



Cheers Jeff. :) I would have to agree that there comes a point where the quantity of processing delivers almost diminishing returns. Depending on the quality of the data, you’ll either spend more or less time processing.



Thanks Glen. I’m getting around to your imaging request. Stay tuned…:D



Cheers Matty P. :) Thanks for checking it out.



Thanks Graeme. :thumbsup: Was certainly a tight fit in the FSQ/STL11k frame (155.8 x 233.7 arcmin).



Cheers Alchemy. :thumbsup: Interesting way of viewing a post – look at others peoples comments first before viewing the image. I typically first look for the instrument and camera used (if posted), then check out the image before making a comment. Thanks again.:)



Thanks Peter. Appreciate it. :thumbsup:



Cheers Ian. :) It is an interesting and challenging imaging target that for sure.:thumbsup:

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Thanks all for taking the time to check out the image and make comment.:)

[Alchemy]

im on a limited download , and as theres no thumbnail ,if it doesnt get a good rap thats where it ends. Not that i ever recall you putting up a dud:D some websites just chew through my limit..... however on yours i will check out the big image... you should submit this one for APOD

[EzyStyles]

BEAUTIFULLLL JASE! one of the best witches head ive seen so far. as always, i can't comment anything negative on your images. this one is too nice.

[iceman]

Very haunting object, beautiful captured and processed, Jase. Another masterpiece.

I love the red star in the heart of the nebula.

[avandonk]

It is a very faint object and you have done well to get such a fine image.

Bert

[Garyh]

Jase! what can I say?....:eyepop::eyepop::eyepop:
I think thats one of the best witchhead neb images I have seen. Visually very pleasing!
I tried this with my tv-genesis and 300d but it didn`t quiet fit into the field of view..another benefit of a big chip!
Very well done!!.:thumbsup:
cheers Gary

[JohnG]

Like others have said, what can one say, a truly haunting picture, got to be one of the best WitchHead shots I have ever seen. An excellent rendition of this truly difficult object. :thumbsup::thumbsup::thumbsup:

Cheers

[Ric]

Hi Jase, a wonderful start to 2008 with a fantastic image. I enjoyed the way you have captured the subtle changes in colour throughout the nebula, I imagine that wasn't an easy task.

A top shot

[danielsun]

As usual another jaw dropper Jase !!:eyepop:
Truly brilliant :thumbsup:

[jase]

Cheers Eric. You’re too kind. ;) The more I look at it, the more I think I could have done things differently – whether it would have improved on this rendition is a different story.



Thanks Mike. Agree, the orange star (spectral type K and K0) make a nice statement amongst the contrasting nebulosity.:)



I’m surprised others haven’t given this target much attention Bert.:shrug: It is a tough target, but that’s what makes it all the more rewarding. Thanks again.:thumbsup:


Cheers Gary. :thumbsup: You could always mosaic it with the Gen/300d. That was my original intention as I thought capturing two individual frames would give much better control over the contrast/intensity levels from Rigel. After careful planning, I thought I’d try taking up the challenge of fitting it all in one frame. Seems to have work reasonably well.:)



Thanks John. Appreciate the kind words.:thumbsup::)



Cheers Ric. :thumbsup: The dusty characteristics of the reflection nebula resulted in different hues and tones. I’ve seen some images others have done which have not picked this up. I attribute this to acquiring the data when it’s high, specifically the blue channel to minimise atmospheric extinction. I knew I was onto something when the raw blue subs displayed few background galaxies such as spiral galaxy NGC1752(mag 12.6), PGC16607(mag 14.8), PGC16669(mag 14.7), PGC1015512(mag 15.1) and PGC16941(mag 16.8).:D


Cheers Daniel. Thanks for taking the time to review and make comment.:thumbsup:

[Tamtarn]

As all have commented another very special image Jase.

The intricate detail in the dusty nebulosity that you have managed to capture have enhanced the Witchead more than we have seen in any other image of this DSO and it reveals much more detail of the eye nose cheeks and mouth. One cannot see it as anything else other than a witches head.

Just Wonderful!!

Barb and David

[citivolus]

It is amazing what you are shooting these days. Compare this to http://www.astrosurf.com/lorenzi/poss/witchhead.htm taken on the 1.2m Palomar scope. Not bad for a little refractor.

[RB]

What dark majik is this ??
Is this a promotional poster for Macbeth ??? :lol:

One of the best versions of The Witchhead that I've ever seen Jase !!!

Even the kids thought it was fantastic.

Once again congrats on another wonderful image.

:thumbsup:

[jase]

Thanks Barb and David.:) Pleased you liked it. Was going to collect more data on this target, but felt the urge to move on to other targets. The nights are way too short.



Thanks Citivolus.:) It helps to have dark skies and a sensitive chip. The FSQ is also a fine instrument.



:lol: Cheers RB. A fun “fairy tale” target for the kids. :thumbsup:

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Talking about productivity…
Over the past three nights, I’ve collected 11.5 hours (46subs – 15min each) of RGB data over two targets, one a mosaic. The frustrating thing is I’ve got nothing to show for it as I still need more data. This hobby sure tests ones patients…

[zipdrive]

WOW!! Beautiful!
always look forward to seeing your work!!

[ballaratdragons]

Very nice work, Jase. The detail in the full res image is astounding!!!

I spotted some nice little galaxies (see below). Two in the upper left and a close pairing on the right :thumbsup:

[2020BC]

Wonderful. This is the best shot I've seen of this nebula. :thumbsup: The witch looks like she's looking at the star Rigel and gasping, and you can tell that it is the star that is lighting her face. Well worth all the effort, Jase.:thumbsup:

[dugnsuz]

Holy Focaccia jase!!!!!
Very entertaining image - great composition and processing.
Thanks for providing us with inspiring images like this one.
Cheers
Doug

[Jazza]

Yeah... that is a seriously nice one :D

[glenc]

The two galaxies in pic 1 are NGC 1752 (mag 13.3) and PGC 16607 (mag 14.8) according to Guide8.

[jase]

Thanks for checking out the image and making comment Dave. Appreciate it.:)



Cheers Ken. :thumbsup: There are actually a few others in there as well. Really need some aperture to pick more of these faint PGC galaxies out. Still for a small 4” (106mm) aperture instrument, it’s not a bad effort.



Thanks Bill.:) It’s is certainly an interesting reflection nebula.



Pleased you liked it Doug. Thanks.:)



Thanks Jazza :thumbsup:



Yep, that’s them Glen. :) I was looking at TheSky. There’s a considerable bunch of PGC galaxies between the nebulosity and Rigel, however I didn’t pick many up.

[montewilson]

HI Jase - Congratulations on your image. Actually, I was delighted to see it because it cleared up something for me.

In your image there is a small patch of darker nebulosity that is not blue. I have this too but as I saw it in no other shots of this object, I assumed it was a gradient problem with my green channel. I feel much better to see it is real.

Here is a greatly compressed jpg of mine. I took it at 2x2(RGB) on the FSQ with the STL. I think each image is a 5 min exposure and there were 4 shots for each colour so about one hour in total. None the less I think I will have to be careful of skyglow at 2x2, my kit is very sensitive at this setting.

Yours is quite a piece of work - well done. PS - I saw those galaxies in mine too.... Very cute.

[jase]

Thanks Monte. :thumbsup: You've also captured it nicely. Those three stars in a row at the top of your frame is what caused flares in my image. I did have problems with the green channel. Not a very severe gradient, but enough to cause some processing challenges. I thought about binning the RGB data on this and also other images for the FSQ/STL11k combo, but seriously in its native 1x1 its already running at 3.5 arcsec/pixel. A 2x2 bin delivers 7 arcsec/pixel which is a significant hit on resolution. If you're taking lum at 1x1, then you'd probably be ok, though I've seen another person on the SBIG forums produce an L 1x1 and RGB 2x2 with a similar set up and to be really honest, I didn't like it. It could have been the way it was processed, but the RGB data caused the colour to "spill" into surrounding pixels of the stars. Everything looked well aligned. Perhaps the use of the minimum filter on the combined RGB data would have rectified this, but it wasn't an ideal solution. All my FSQ images are 1x1 for Lum and RGB. For this image, the blue channel was also used as the Lum so a 1x1 was the best method. Thanks again for your comments. I hope to see more of your FSQ images soon - been too quiet, you need to get out there.:)

[montewilson]

Yes - its been a while. I haven't got much to show at the moment. I am having a review of my techniques. I am not really happy with the results I am getting. I will pick your brains later about that topic later. There are issues with darks and exposure times that need to be resolved before I will get results comensurate with my equipment.

Sometimes I feel like an L Plating kid in a top fuel dragster with this equipment. While I can get from one end of the street to the other, I usually hit a few telegraphpoles on the way. I know it is possible, you seem to do 5 sec quarter miles every time haha.....

As for the 2x2 it was a bit of a departure from the norm for me but I was curious to see how much I could get of the object in the limited time I had.

[coldspace]

Unreal image, Makes me love this hobby even more. Keep up the fantastic work, must be very satisfying after many hours of patience to end up with a final prize like that :eyepop:.Well done and keep posting.

Matt.

[Ingo]

Excellent image, I've been wanting to image this since the day I got into astrophotography. I don't have a cooled camera though, so no use! Great image!!!

[Starkler]

Amazing image that looks like a piece of astro concept art, if such a thing exists.

[cwjames]

Hi Jase,

That image is really something (Great that is).

Not sure what process you use when collecting the data over multiple evenings to ensure your frames match up ?

Really great work !

Chris

[jase]

:lol: Nice analogy Monte. :lol: Providing you’re still getting out there and getting some quality time with the instrument, that’s all that counts. Skills will not evolve with equipment sitting in a garage collecting dust instead of photons.



Cheers Matt. :thumbsup: I get the biggest kick out of the planning and image processing. The latter in particular as this is where the image comes alive.



Thanks Ingo. What’s holding you back Follow your instincts to seek gratification. Don’t limit yourself because of your equipment. You only have to look around on this forum to see the great work done by others with uncooled modded/unmodded DSLRs.



Cheers Geoff. :) Astro concept art. – sounds cool. I’ve always been fascinated by the artist presentations of a distant worlds in some of the astro mags. These guys have some incredible imagination.



Thanks Chris. Frame alignment is done through a telescope pointing model and a plate solving process. This ensures the center of the image is perfectly aligned with arcsecond precision. Providing I don’t rotate the Tak CAA, I can shoot an object for as long as I need, night after night (weather permitting of course).

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Once again, thank you all for your supportive and kind responses. Much appreciated.:)