Dark Knight Rises

Horsehead Nebula
Image Credit; Purnendu Gupta

Dense black clouds resembling the bust of a horse tower over a backdrop of a glowing red veil. Like a black knight in chess. The gash of red across, billowing black rising with dabs of blues - gives rise to a magnificent, almost ominous scene. Nature's watercolor of a knight about to make its move in a celestial chess game at play.

The Horsehead nebula (Barnard 33) is a dark nebula in Orion. Among the night sky wonders I have seen - this is perhaps the closest resemblance of the object to its common name. But its existence was unknown till a hundred years after the discovery of the nebulosity.

Maid of Honor

Williamina Fleming.
Source: Wikimedia Commons

The Horsehead nebula is visually very difficult to make out due to its small angular size and faintness. It was actually discovered photographically in 1888, by Williamina Fleming employed at Harvard Observatory. While scanning photographic plates as part of her spectrographic work, she noted "a semicircular indentation 5 minutes in diameter, 30 minutes to the south of Zeta Orionis".  Note that IC 434, the red glowing veil in the picture, which is an emission nebula IC 434, had been discovered by astronomer William Herschel as early as 1786. But nearly a hundred years had passed before Fleming for the first time, put a finger on it.

It is interesting to note that Fleming had started work as a maid at the house of Professor Pickering - director of Harvard College Observatory. She was appointed to an administrative role at the observatory after Pickering's wife noted her talents. She moved on to become one of Professor Pickering's female "computers" (of "The Glass Universe" fame) and has many honors to her credit, the discovery of the Horsehead being one among them.

Zero Dark Thirty Three

E.E. Barnard
Source: Wikimedia Commons

For a long time, this region was thought of as a starless patch. A hole in the background emission nebula. Twenty five years after discovery, in 1913, in a paper titled "Dark Regions in the Sky Suggesting an Obscuration of Light" astronomer Edward E. Barnard claimed it to be not a vacant spot but a dark nebula. A read of Barnard's paper suggests there is perhaps more intuition and expert judgement at play here than well developed objective analytical techniques. Born a semi-orphan and with little formal education, and presumably self taught skills, Barnard was in fact a photographer first, and became a photographers assistant at the tender age of nine. Interestingly, he was a successful comet hunter and had built his first house with reward money he had obtained by discovering five comets for $200 each (among many more to his name)!


Barnard had been recording dark nebula in the Milky Way and he cataloged the Horsehead as no. 33 in his list. Hence the name Barnard 33.

Taming the Horse:

About 1300 light years away, the Horsehead nebula is 4 lightyears tall and 3 lightyears wide but very difficult to observe in small scopes due to its small angular size and faintness and easier target photographically. The image came to me several attempts and learnings later. it seemed just in time before winter bows out this year. The imaging method used narrowband multi-pass filters and 2.5 hours of exposure over two nights from my backyard.

It is very satisfying to note the same image features - albeit in negative greyscale in Barnard's image as in mine. This includes the reflection nebula to the lower left of image, the major stars and of course emission and dark nebulae IC 434 and Barnard 33 respectively.

I feel humbled that we can have in full Technicolor today, what top of the line professionals only a hundred years ago could only dream of (in black and white).

It's a good time to be alive!



Imaging details:
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Canon 70D unmodified
35X 300s light, 20 dark, 20 Bias, 10 Flat ISO 800
Optolong L-enhance
Celestron 127 mm Mak-Cass scope with 0.6X focal reducer
Celestron AVX mount, electronic focuser
Orion 50mm guidescope and ZWO ASI 120 mm guide camera
Capture Software: CPWI, PHD2, APT, NINA
Processing: DeepSkyStacker, Topaz DeNoise AI, GIMP