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Wednesday, January 7, 2015

Cygnus Wall in visual colors

This photo is originally published at 31.10. last year. At the time I made only a mapped color version of it.
Now I'm publishing the same image in visual spectrum. It's combined from three component exposures of an emission from the ionized elements, hydrogen , oxygen and sulfur. (H-alpha, O-III and S-II) Channels are combined by following method, Red = 75%H-alpha + 25%S-II Green = O-III and Blue = 80%O-III+20%H-alpha (to compensate otherwise missing H-beta emission.)

The Cygnus Wall, a part of the much larger North america Nebula, NGC 7000. This is a relatively bright formation, three hours of H-alpha light and half an hour of O-III was captured for this photo. S-II channel is borrowed from an older wide field image, since the clouds rolled in before I was able to shoot it.

Cygnus Wall
Click for a large image

Image is in visual spectrum from an emission of  the ionized elements. 
The Red glow is mainly from ionized hydrogen, bluish hues are from ionized oxygen.

Detail from the image above


The North America nebula on the sky can do what the North America continent on Earth cannot -- form stars. Specifically, in analogy to the Earth-confined continent, the bright part that appears as Central America and Mexico is actually a hot bed of gas, dust, and newly formed stars known as the Cygnus Wall. The above image shows the star forming wall lit and eroded by bright young stars, and partly hidden by the dark dust they have created. The part of the North America nebula (NGC 7000) shown spans about 15 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).

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-aplha
Astrodon filter, 3nm O-III

Exposure times
H-alpha 6 x 1200s = 3h
O-III 3 x 600s = 30min. 
S-II is borrowed from my older wide field image


The area of interest is marked as a white rectangle, Photo is in mapped colors.

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

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