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Sunday, May 29, 2011

The "Bubble Nebula", 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.

Sharpless 162, NGC 7635, the "Bubble Nebula"

Ra 23h 20m 48s Dec +61° 12′ 06″

NOTE. The size of the full Moon (0,5 degrees) is marked as a gray circle in all of the images.
Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. Star colors are mixed from the NB channels, Red=H-a, G=O-III and B= 85%O-III + 15%H-a.This composition is very close to a visual spectrum.

Images used in the series above from top to bottom

  1. A wide field mosaic from the Bubble and Sharpless 157 to the Wizard Nebula at Right. Images are taken with a Tokina AT-X 300mm camera lens. 
  2. A Sh2-157 and Bubble Nebula part of the mosaic, Tokina AT-X 300mm 
  3. Zoomed in version from the previous image 
  4. A close up of the Bubble Nebula imaged with a Meade LX200 GPS 12" telescope, focal lenght ~2000mm. 
  5. A zoomed in version of image above.
Links to the original images, used in series, from top to bottom

This is one of the most interesting looking structures in the sky!
NGC 7635 aka "Bubble Nebula, Sh2-162 or Caldwell11, is a Hydrogen emission nebula in constellation Cassiopeia. It locates near the open cluster M 52 at distance of about 11.000 light years from the Earth.
The bubble structure is created by a strong stellar wind, a radiation pressure, from massive hot magnitude 8,7 central star, SAO 20575, it can be seen in an image inside of the bubble, off centered at Right.
Bubble is an expanding shock front inside a giant molecular cloud and it has a diameter more than Six light years. The spherical formation is expanding at speed of 6500.000 km/h, due the huge scale and distance we can't see the movement easily. In a century, the bubble in this image will be only about one pixel wider, than now! ( ~1 arc second)Strong UV-radiation from a central star ionized elements in a gas and makes them glow at typical wavelength to each element. (Hydrogen glows Red light as Sulfur, Oxygen emits Green/Blue light at visible wavelengths) 

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