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Monday, July 18, 2011

The "Crescent Nebula", NGC6888, apparent scale in the sky

I have shot many targets with several focal lengths. 
Due that, I will publish some of my material as an image sets, with different field of view and detail levels.
The fractal nature of our universe stands out nicely by this way and it will make the orientation more easy.

Many times, it's difficult to understand the image scale of astronomical images.
Due that, I will add a Moon circle in some of the images to show the angular scale in a sky. 
The full Moon has an angular size of ~30 arc minutes, that's equal to ~0,5 degrees.

NGC 6888, the "Crescent Nebula"
Ra  20h 12m 7 Dec +38° 21′ 3", in Cygnus

Images are in HST-palette, (HST=Hubble Space Telescope)
from the emission of ionized elements, R=Sulfur, G=Hydrogen and B=Oxygen.
Star colors are mixed from the NB channels, Red=H-a, G=O-III and B= 85%O-III + 15%H-a.
NOTE. The size of the full Moon (0,5 degrees) is marked as a gray circle in all of the images.

This is a second version. First one, as a Hubble palette composition, can be found here:

Images used in the series above, from top to bottom

1. Three panel mosaic of the "Cygnus Trio", Tokina AT-X 300mm f2.8 camera lens.
2. Two panels from a mosaic above, Tokina AT-X 300mm f2.8 camera lens.
3.  wide field image of NGC6888 was shot with a Tokina AT-X 300mm f2.8 camera lens.
4. Closeup images, at the bottom are shot with a Meade LX200 GPS 12" reduced ~2000mm.
Baader narrowband filter set was used with all of the  images, wide fields are shot with a QHY8 and closeup with QHY9 cooled astronomical camera.

Original images used for image series can be found here:

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