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Tarantula Nebula: HDR H-Line Rendering, Alex Woronow

Tarantula Nebula: HDR H-Line Rendering

Getting plate-solving status, please wait...
Tarantula Nebula: HDR H-Line Rendering, Alex Woronow

Tarantula Nebula: HDR H-Line Rendering

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Description

Tarantula Nebul: HDR H-Line Rendering

OTA: TAO 150 (f/7.3)

Camera: FLI - ML16200 (1.13 arcseconds/pixel)

Observatory: Deep Sky West, Chile

EXPOSURES:

Red………15 x 600 & 38 x 120 sec.

Blue……..33 x 600 & 27 x 120

Green…..27 x 600 & 24 x 120

L……………29 x 600 & 10 x 120

H…………..14 x 900 & 24 x 300

S……………15 x 900

O…………..20 x 1800

Total exposure: 39.9 hours

Image Width: 1.4 deg

Processed by Alex Woronow (2020) using PixInsight, Aurora, Topaz, SWT

This image of the Tarantula Nebula was targeted to reveal the structures of the Hydrogen gas component of the nebula. The colors are based on the SHORGB, with each narrowband image integrated into its respective broadband parent. Some H-beta was synthesized for the blue at a ratio of H-alpha/H-beta =2.9. (Where there’s Ha, there always Hb.) The method I used for this narrowband-broadband fusion is described here:

https://pixinsight.com/forum/index.php?threads/blending-ha-with-red-a-new-approach.10728/

Recently I saw an image by Vadim Kozatchenko on Astrobin that used H-line to bring out detail in M31. (Thanks to Vadim for answering my inquiry on how he did his amazing image.) Then, though I, the method I use for blending H into the Red channel calculates, along the way, the H-line intensity, devoid of the background red radiation. So why not do essentially the same thing as Vadim did, but a bit more rigorously, perhaps. Then, the calculated H-line intensities became the L channel in the image. The result is an image with the colors as described above, but with the structure of the H-alpha emissions.

At that point, it seemed to me that stars played no significant role in the structure of the H-alpha emissions, the topic of this image, so I invoked Starnet++ (PI version) to remove them.

Finally, a note on the wealth of data used in this image. I have subscribed to the TAO150 operated by Deep Sky West in Chile since it became operational. The scope has had two different cameras over that span and has imaged the Tarantula Nebula once with each. I combined the best images from both cameras for this exercise—a total of 277 subs and close to 40hrs of exposure time…WOW! Also, both cameras had captured most filters at two different exposures, enabling HDR processing. The one problem was that the rotation angles of the two cameras differed by about 15 degrees, but there were adequate exposures to ameliorate this problem. All-in-all this is the largest, most complex image processing project I have undertaken to date.

Hope you enjoy this rendering. In the coming days, I will post some additional interesting views of the Tarantula via H-line rendering.

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Tarantula Nebula: HDR H-Line Rendering, Alex Woronow