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Sunday, November 2, 2014

Sharpless 115 and a planetary nebula Abell 71

I have always wanted to shoot this complex nebula and planetary in Cygnus. The object is kind of dim and has lots of details. Actually it's so complex, that I had a hard time trying to figure out how to make a nice composition out of it.

Sharpless 115, Sh2-115 and Abell 71
A square of birth and death
Click for a large image

Mapped colors from an emission of the ionized elements, Red=Sulfur, Green=Hydrogen and the Blue =Oxygen.The bright spot at lower left is the Abell 71, PLN 85+4.1

Closeups from the image above

Abell 71, PLN 85+4.1

Image in visual colors

Image in visual spectrum composed from emission line channels, H-a, O-III and S-II

A starless version

Sometimes I'm publishing experimental starless versions of my photos. The actual nebula stands out nicely by that way.


 Sharpless 115 stands just north and west of Deneb, the alpha star of Cygnus the Swan in planet Earth's skies. Noted in the 1959 catalog by astronomer Stewart Sharpless (as Sh2-115) the faint but lovely emission nebula lies along the edge of one of the outer Milky Way's giant molecular clouds, about 7,500 light-years away. Shining with the light of ionized atoms of hydrogen, sulfur, and oxygen in this Hubble palette color composite image, the nebular glow is powered by hot stars in star cluster Berkeley 90. The cluster stars are likely only 100 million years old or so and are still embedded in Sharpless 115. But the stars' strong winds and radiation have cleared away much of their dusty, natal cloud. At the emission nebula's estimated distance, this cosmic close-up spans just under 100 light-years.


Sharpless 115 and the Abell 71 can be seen in this older wide field image of the Cygnus nebula complex.
More info about this image can be seen HERE.

Technical details

Processing work flow
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack2.
Deconvolution with a CCDStack2 Positive Constraint, 33 iterations, added at 50% weight
Color combine in PS CS3
Levels and curves in PS CS3.

Imaging optics
Celestron Edge HD 1100 @ f7 with 0,7 focal reducer for Edge HD 1100 telescope

Cameras and filters
Imaging camera Apogee Alta U16 and Apogee seven slot filter wheel
Guider camera, Lodestar x2
Astrodon filter, 5nm H-alpha
Astrodon filter, 3nm O-III

Exposure times
H-alpha, 18 x 1200s = 6h
O-III, 6 x 1200s = 2h
S-II, 3x1200s = 1h

A single un cropped, calibrated and stretched 20 min. H-alpha frame

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