Hemisphere:  Northern
Sh2-140 - The Hidden Nebula, 


            Jason Guenzel
Sh2-140 - The Hidden Nebula
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Sh2-140 - The Hidden Nebula

Technical card

Imaging telescopes or lenses: CELESTRON EdgeHD 800

Imaging cameras: ZWO ASI1600MM-Cool

Mounts: Orion Atlas Pro AZ/EQ-G

Guiding telescopes or lenses: CELESTRON EdgeHD 800

Guiding cameras: ASI120MM

Focal reducers: Celestron 0.7x Focal Reducer

Software: PixInsight  ·  Sequence Generator Pro  ·  Adobe Photoshop  ·  PHD 2

Filters: Astronomik L-3 UV-IR Block 1.25"  ·  Astronomik Deep-Sky G 1.25"  ·  Astronomik Deep-Sky R 1.25"  ·  Astronomik Deep-Sky B 1.25"  ·  Astronomik H-alpha 6nm CCD 1.25"

Accessory: Moonlite CHL 2.5" Large Format Crayford Edge Focuser  ·  Orion Thin Off-Axis Guider (TOAG)

Dates:Sept. 27, 2018Sept. 28, 2018Oct. 8, 2018Oct. 9, 2018Oct. 10, 2018Oct. 14, 2018Oct. 15, 2018Oct. 16, 2018Oct. 17, 2018Oct. 18, 2018Oct. 19, 2018Oct. 22, 2018

Astronomik Deep-Sky B 1.25": 30x240" (gain: 0.00) -20C bin 1x1
Astronomik Deep-Sky G 1.25": 30x240" (gain: 0.00) -20C bin 1x1
Astronomik Deep-Sky R 1.25": 30x240" (gain: 0.00) -20C bin 1x1
Astronomik H-alpha 6nm CCD 1.25": 200x240" (gain: 139.00) -20C bin 1x1
Astronomik L-3 UV-IR Block 1.25": 237x180" (gain: 0.00) -20C bin 1x1

Integration: 31.2 hours

Darks: ~50

Flats: ~50

Bias: ~256

Avg. Moon age: 10.33 days

Avg. Moon phase: 49.40%

Bortle Dark-Sky Scale: 5.00

Basic astrometry details

Astrometry.net job: 2373396

RA center: 22h 19' 19"

DEC center: +63° 18' 36"

Pixel scale: 0.526 arcsec/pixel

Orientation: 90.659 degrees

Field radius: 0.383 degrees

Resolution: 4236x3078

Data source: Backyard


This view into deep space reveals a pocket of hydrogen emission (Ha) peeking out behind a large dust cloud. Fortunately, looking with high magnification reveals some additional detail. You can see towering wisps and columns of Ha gas, but the foreground dark nebula obscures the view just as it gets interesting! It kind of makes you want to peek around the corner, doesn't it? Scientific studies in the infrared have indicated a cluster of young energetic stars inhabit this pocket and are actively working to shape these structures.

This area of space is catalogued under a few different names. Sharpless2-140 (Sh2-140) refers to the hydrogen alpha emission and Lynd's 1204/2304 (LDN 1204/2304) is the dark nebula throughout frame. It is immediately apparent that the dark nebula hangs in front due to the lack of stars in the area. There are actually a few interesting features here too, in particular a miniature dark snake to the upper left.

The stars in this image were quite overpowering, as was the brightness of the central pocket. I dimmed down both in postprocessing in an effort to reveal the structure to the observer. I hope it worked! Though this is not an tremendously uncommon target, the inner detail is not something you see every day so I focused on showcasing that as best as I could. I've taken up the hobby of visualizing where these objects are in the "big picture". It sits in Cepheus, between roughly between the more commonly imaged Lobster Claw and the Squid.




Jason Guenzel
License: None (All rights reserved)

Sky plot

Sky plot


Sh2-140 - The Hidden Nebula, 


            Jason Guenzel