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Thursday, March 3, 2011

The "Bubble Nebula" reprocessed

Since my processing technique gets better and weather doesn't give any support, I have reprocessed some older images. There is now star colors added and other processing is tweaked too.

Sharpless 162, NGC 7635, the "Bubble Nebula"
Ra 23h 20m 48s Dec +61° 12′ 06″

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.

A closeup

This is one of the most interesting looking structures in a 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) 
If you are interested about color schemes used in my images, I wrote a small study about them, please, have a look here:

Image is in HST-palette, (HST=Hubble Space Telescope) from the emission of ionized elements, R=Sulfur, G=Hydrogen & B=Oxygen.Star colors are mixed from the NB channels, Red=H-a, G=O-III & B= 85%O-III + 15%H-a.

A full, none cropped, image area

Image is shot with a QHY9 and the Meade LX200 GPS 12" @ f5, pixel scale 0.65pixels/arc second.
Original versions from October 2009, with technical details:

Due the small angular scale of bubble itself, about 5,4' x 4,9', (0,09 x 0,08 degrees) this Nebula is hard to capture with details. In this image, the size of the full Moon is marked as a gray circle for a scale. (Moon has an angular size of the 30', that's a 0,5 degrees)
NOTE! The Wikipedia states, that angular size of the Bubble Nebula is 15' x 8'. There must be outer formations included, not just the bubble.

A  wider field image of the region, Bubble can be seen at ten a clock position as a bright "pearl".
Gray circle shows the size of the full Moon.

Some 3D-studies out of this 2D-image.

Parallel vision Stereo Pair 3D:

Cross vision Stereo Pair 3D:

An anaglyph Red/Cyan 3D:

Still motion animations of the Buble Nebula

Zoom in:

Zoom out:

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