Negev Desert, Israel

SBIG ST8300M, Astrodon filters: RGB E-Series GenII, Ha 5nm
L(Ha)R(Ha)GB Total 2:55 hours = L(Ha) 80 min. [16x5 min.] + R,G,B 5x5 min. each
Boren-Simon 2.8-8 CF (Carbon Fiber) OTA - http://www.powernewts.com
EQ6 mount, guided w/PHD and EQMOD

The Soap Bubble Nebula (PN G75.5+1.7)

The Soap bubble nebula, or PN G75.5+1.7, is a planetary nebula in the constellation Cygnus, near the Crescent Nebula (NGC 6888, see below). In this image it is the "bubble" seen at the very middle of the image, about a third of the way down from the top. It's apparent dimensions are 4'20".

A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life. The name "planetary nebula" originated with this type of object's first discovery in the 18th century because of its similarity in appearance to giant planets when viewed through small optical telescopes, and is otherwise unrelated to the planets of the solar system.

At the end of the star's life, during the red giant phase, the outer layers of the star are expelled via pulsations and strong stellar winds. Without these opaque layers, the hot, luminous core emits ultraviolet radiation that ionizes the ejected outer layers of the star. This energized shell radiates as a planetary nebula. Planetary nebulae are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.

The Soap Bubble nebula is quite unique, in the sense that it was only recenly discovered by amateur (!) astronomer Dave Jurasevich using a 160 mm refractor telescope, who imaged the nebula on June 19th 2007 and on July 6th 2008. The nebula was later independently noted and reported to the International Astronomical Union by Keith. B. Quattrocchi and Mel Helm who imaged PN G75.5+1.7 on July 17th 2008.

The Crescent Nebula (NGC 6888 or Caldwell 27)

The Crescent Nebula (NGC 6888 or Caldwell 27) is the emission nebula at the bottom of this image. It lies about 5000 light years away, and is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward. The inward moving shock wave heats the stellar wind to X-ray emitting temperatures. [Ref. http://en.wikipedia.org/wiki/Soap_bubble_nebula http://en.wikipedia.org/wiki/Planetary_nebula http://en.wikipedia.org/wiki/Crescent_Nebula].

Open Cluster (IC 4996)

Finally, the open cluster IC 4996 can be seen on the top left side of this image.