In the Shadow of the Horsehead - Deep 26 Hour Version

[SkyViking (Rolf)]

Hi All,

I recently added a Ha filter to my collection and promptly put it to the test by soaking up a decent amount of data on the Horsehead nebula.
I wanted to improve on my initial attempt on this target from 2014. One of the issues was that I'd like to show the delicate 'curtain' structure of IC 434, the bright glowing hydrogen emission that the Horsehead is silhouetted against.
This also prompted me to add more data to the LRGB channels as well, in order to bring out the faint dust details better. So all together with last year's data I ended up with over 26 hours of data which I completely reprocessed and assembled into this updated version.
I'm pleased that the result has higher resolution and more depth than last years' effort. The colours are also richer and more refined and in particular the Ha curtains now stand out above and around the Horsehead.

Link to full resolution image (3.8MB)
Link to large 'X3' size image
Link to large 'X3' size greyscale version

About the image:
The Horsehead Nebula (also known as Barnard 33) is without doubt one of the most recognized and fascinating objects in the sky. This iconic feature is formed by the sharp outline of a dark dust cloud, with a remarkable likeness to a horse's head, silhouetted against a brightly glowing patch of ionized Hydrogen (IC434) that is being energized by the hard ultraviolet radiation from nearby Sigma Orionis, a quintuplet star system lying just outside the top of the image.

I sought to process this image to show not only the Horsehead silhouette but also the details of the dense dust cloud (Lynds 1630 molecular cloud) from which it emerges.
The background behind the Horsehead glows with a soft diffuse reddish/pinkish light because of strong emission by spectral lines from ionized Hydrogen. Visible in the foreground is the large looming shadow being cast by the Horsehead's tower of dust, appearing as a dark fan-shape down towards the bottom centre-left, intercepted on its left edge by the intricate bright blue reflection nebula NGC2023. In contrast to the red emission glow, the reflection nebula is caused by light from the nebula's bright blue central stars which is being reflected off the surrounding dust.The brightest member of the central cluster is the B star HD 37903, a very young star with intense ultraviolet radiation that has carved a four light years wide cavity in the dust that we see as the reflection nebula.

Throughout the dark cloud, both in and below the Horsehead, are several small glowing reddish patches. These are the feeble lights from new stars being born in the cloud. Some of these are Herbig-Haro objects; the result of plasma jets ejected from young protostars which collide with the surrounding gas and dust and cause the glowing emission.
Inside the bright blue nebula NGC2023 are also several brightly coloured wisps of emission patches, further hints of young stellar objects and the regions' overall complexity and beauty.

The Horsehead Nebula was discovered in 1888 by Williamina Fleming on a photographic plate (#B2312) taken at Harvard College Observatory. She described the bright emission nebula later designated IC434 as having “a semicircular indentation 5 minutes in diameter 30 minutes south of Zeta [Orionis].”
She was never credited with the discovery though because Dreyer did not include her name when he compiled the Index Catalogue (IC) in 1895 and 1908.

Image details:
Date: 7th, 8th, 9th, 20th, 26th, 27th, 28th, 31st December 2013
2nd, 5th, 6th, 9th January 2014
23th December 2014
1st, 2nd, 3rd, 5th, 6th, 10th, 11th, 13th, 14th, 15th, 18th, 20th January 2015
Exposure: HaLRGB: 795:556:105:60 mins, total 26 hours 21 mins @ -25C
Telescope: 12.5" f/4 Serrurier Truss Newtonian
Camera: QSI 683wsg with Lodestar guider
Filters: Astrodon LRGB E-Series Gen 2
Taken from my observatory in Auckland, New Zealand

To enjoy the best view please check the links to the high resolution version above. Attached below is a small version plus a greyscale version to show the intriguing contrasts and details of the area.
All comments welcome as usual.

Regards,
Rolf

[rmuhlack (Richard)]

That is really special - another benchmark image

[Placidus (Mike and Trish)]

Very special indeed. I like the way you've preserved the fine detail inside NGC 2023.

[alpal]

Hi Rolf,
that's a beautiful sharp picture with plenty of colour.
You are getting top results from your 12" f4.

cheers
Allan

[Paul Haese]

Good colour and detail Rolf. The saturation is very pleasing. The full res image is quite interesting to view.

[pluto (Hugh)]

That's a great image!
So much detail and so much shape to the HH, excellent work

[suma126 (Shane)]

great work rolf love your images

[RickS (Rick)]

One of the best horseheads that I've seen. Masterfully done, Rolf!

[strongmanmike (Michael)]

Of course, it is an excellent image (goes without saying) but... when I compare this to your earlier version I have that notorious "maybe a combination of the two would be peeeerfect" feeling that can occur with repros This latest version certainly highlights the curtain striations but the magenta (and I have nothing against magenta remember ) seems slightly too strong, the earlier version is a little redder and has less harshness and less noise and reveals more dust and stars

Might be worth a try?

Great stuff regardless and the B&W version does look excellent

Mike

[gregbradley]

Fabulous image Rolf. I like your images they are always top notch.

Greg.

[multiweb (Marc)]

That's superb Rolf. Amazing colors and details. Sub zero cool.

[Andy01 (Andy)]

Originally Posted by strongmanmike

the magenta (and I have nothing against magenta remember ) seems slightly too strong

This is a standout, benchmark image - technically stunning and beautifully processed. However I have to agree with Mike, it's way too magenta for my taste and imo it loses impact that would be there from a bolder red.

Not that I'm any kind of expert mind you, the standard of this image is something I would one day aspire to, well done indeed

Andy

[AstroJason (Jason)]

This looks incredible Rolf. I really like the colour and curtain structure you have brought out in this. Keep them coming Rolf.

Cheers,

Jason

[Leonardo70 (Leonardo Orazi)]

Very nice Rolf. Great image.

All the best,
Leo

[Ross G]

What a beautiful Horse Head photo Rolf.

One of the best I have ever seen!

Ross.

[SkyViking (Rolf)]

Originally Posted by rmuhlack

That is really special - another benchmark image

Thank you Richard!

Originally Posted by Placidus

Very special indeed. I like the way you've preserved the fine detail inside NGC 2023.

Thanks Mike, yes NGC2023 is in my opinion overlooked due to its proximity to the Horsehead, so I deliberately wanted to bring it out.

Originally Posted by alpal

Hi Rolf,
that's a beautiful sharp picture with plenty of colour.
You are getting top results from your 12" f4.

cheers
Allan

Thank you Allan, I do enjoy the 12.5" f.4 scope, and it is well suited to the KAF-8300 chip.

Originally Posted by Paul Haese

Good colour and detail Rolf. The saturation is very pleasing. The full res image is quite interesting to view.

Thank you Paul, I'm glad you like the saturation level because I did experiment a bit with that here in order to find the right balance.

Originally Posted by pluto

That's a great image!
So much detail and so much shape to the HH, excellent work

Thanks very much Hugh, the H-alpha really helped sharpen up the HH and curtains.

Originally Posted by suma126

great work rolf love your images

Thanks for your kind words Shane

Originally Posted by RickS

One of the best horseheads that I've seen. Masterfully done, Rolf!

Thanks a lot Rick, I'm very happy with the result and glad you enjoyed it!

Originally Posted by strongmanmike

Of course, it is an excellent image (goes without saying) but... when I compare this to your earlier version I have that notorious "maybe a combination of the two would be peeeerfect" feeling that can occur with repros This latest version certainly highlights the curtain striations but the magenta (and I have nothing against magenta remember ) seems slightly too strong, the earlier version is a little redder and has less harshness and less noise and reveals more dust and stars

Might be worth a try?

Great stuff regardless and the B&W version does look excellent

Mike

Thank you Mike, and thanks for the feedback. I'll have to differ regarding the noise level though. The old image definitely has a lot more noise, but that was somewhat masked by poor noise reduction, and when comparing with the new version I feel the old one has a bit of that (IMO) dreaded 'plastic' look due to overprocessing. I've actually deliberately held back on the noise reduction this time around, something which I've grown fond of over the last couple of years.
Re magenta, well that is the natural colour of emission nebulae such as IC 434 so that's what I'd expect to see in this image, but of course the saturation level itself is a matter of taste. ...have I possibly hit your magenta-limit??
The stars were reduced a bit due to the Ha blend which I liked because it helped emphasize the dust and nebulae without resorting to the starless look. Though a starless version would be tempting... I'll have to think about that

Originally Posted by gregbradley

Fabulous image Rolf. I like your images they are always top notch.

Greg.

Thanks very much Greg!

Originally Posted by multiweb

That's superb Rolf. Amazing colors and details. Sub zero cool.

Thank you Marc, too kind!

Originally Posted by Andy01

This is a standout, benchmark image - technically stunning and beautifully processed. However I have to agree with Mike, it's way too magenta for my taste and imo it loses impact that would be there from a bolder red.

Not that I'm any kind of expert mind you, the standard of this image is something I would one day aspire to, well done indeed

Andy

Thanks very much Andy, re the colour please see my comments to Mike above

Originally Posted by AstroJason

This looks incredible Rolf. I really like the colour and curtain structure you have brought out in this. Keep them coming Rolf.

Cheers,

Jason

Thanks you Jason, I'm glad you liked the details that I specifically felt were lacking in the old image

Originally Posted by Leonardo70

Very nice Rolf. Great image.

All the best,
Leo

Thank you Leo

Originally Posted by Ross G

What a beautiful Horse Head photo Rolf.

One of the best I have ever seen!

Ross.

Thanks a lot Ross, that's very kind of you!

[Ric]

Wonderful work Rolf

I really enjoy the way you have brought out the curtain behind the HH.

Cheers

[dvj (John)]

I missed your original post. The grayscale is stunning. A job well done on the processing. Lots of signal, great detail. And the color..... well this is in Gendler, Gabany, Crawford class type of work.

j