The Dumbbell Nebula was the first planetary nebula discovered by Charles Messier in 1764.  John Hershel later coined the "Dumbbell" name.  Even a small telescope shows the distinct hourglass shape with the surrounding egg-shaped cloud of gas.  The central teal color arises from the emission lines of doubly ionized oxygen at wavelengths around 500 nm.  These emission lines can only occur in a low-density environment like that of a planetary nebula. M27 is located approximately 1200 light-years from Earth and is believed to have formed between 3000 and 4000 years ago.  The highly energetic central star, a very hot bluish sub dwarf with a temperature of 85,000 Kelvin, excites the gases in the blown off material to glow on their own.  The shell of gas is approximately 3 light-years across with an apparent diameter of 8.4' x 6.1'. 

IMAGE DETAILS:

• Date & Location:  October 8, 2010  - Bernville, PA

• Weather:  calm, 50F.

• Sky Conditions:  Clear with  average transparency.

• Optics:  TeleVue NP101is Refractor with 1.5x extender = 810mm @ f8.1

• Filter:  Astronomic  EOS clip-in CLS-CCD (Light Pollution Suppression)

• Mount:  Losmandy G-11 equatorial with Gemini V4

• Guiding:  Orion Solitaire w/TeleVue TV60is

• Camera:  Canon T1i (500D) Hap Griffin Modified - Baader UV/IR

• Exposure:  47 min (1 x 4min, 5min, 6min & 4 x 8min) @ ISO800.

• Calibration Frames:  16 Darks & 9 Bias frames

• Processing:  Images Plus 3.82b, Photoshop CS4, NIK.

• Comments:   This is a rather small target for a 4" scope, but I'm fairly happy with this image.  However,  I'd like to try again by increasing the number of light frames to bring out more detail.