NGC 7635 (The Bubble Nebula), and M52.

Note
I softened this image with layer mask somewhat with purpose to get a image with both less contrast and a soft transition to the Ha-data in the nebula.

About
Bubble Nebula. 
NGC 7635, also called the Bubble Nebula and Sharpless 162, is a H II region emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, the 15 ± 5 M☉ SAO 20575 (BD+60 2522).

The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by Friedrich Wilhelm Herschel. The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses.

With an 8 or 10-inch (250 mm) telescope, the nebula is visible as an extremely faint and large shell around the star. The nearby 7th magnitude star on the west hinders observation, but one can view the nebula using averted vision. Using a 16 to 18-inch (460 mm) scope, one can see that the faint nebula is irregular, being elongated in the north south direction.


M52
Messier 52 (also known as M 52 or NGC 7654) is an open cluster in the Cassiopeia constellation. It was discovered by Charles Messier in 1774. M52 can be seen from Earth with binoculars.

Processing
CCD Stack and CS5

Exposure
Lum: 20min, RGB: 20min and
Ha 40min.

Calibration
Darks, bias and flats.

Filters
Baader LRGB. Baader Ha 7nm.

Cooling temp
-20´ C

Mean FWHM
3.91"

Date
August 20th 2011

Location
Krigslida, Stockholm, Sweden.
N59 06 52.4    E 18 03 54.5

Image aqusition
MaximDL Pro

Scope control
Sky X Pro Native drv, and Maxim DL with Astro-Physics V2 drv.

Telescope
TEC APO 140

Mount
Astro-Physics Mach 1 GTO

Camera
QSI 583 WSG

Guiding
OAG guiding with Lodestar Guider

Focus system
Starlight Micro Touch and Focus MAX.


Inverted B/W image


Pure H-alpha