Planetary Nebulae
Expanding shells of gas expelled by some stars at the end of their lives
M27- The Dumbbell Nebula. The first planetary discovered. Imaged at the Cave prime focus. Approximately 25 x 45 sec subexposures stacked.
M57- The Ring nebula in the constellation Lyra; a prototype planetary nebula, the gaseous remnants of a sunlike star at the end of it's life. The star is now a 15th magnitude white dwarf and can easily be seen here in the center. Also seen is the spiral galaxy IC 1296 to the left. More info on M57 can be found here. For a larger view click on the image.
Image Technical Details:

Dates: July-August 2007

Optical system: Cave Astrola newtonian 10" f/7 1778mm. (what is a Cave Astrola newtonian?)

Mount: Paramount ME

Camera: SBIG ST8XME; CFW9 filter wheel; Astrodon Series E LRGB filters; Astronomik 14nm HA filter

Acquisition data: Luminance 36 X 5min; R 15 X 12min; G 15 X 12min; B 18 X 12min; HA 9 X 20min :all fames unbinned (1 x 1); Image scale 1.04 arc sec/ pixel; Average FWHM 2.8 arc sec over all frames; Light box flat frames

Software: CCDsoft v5/ The Sky 6 for acquisition; CCDstack for calibration, alignment and stacking; CCDstack, Photoshop CS for processing.

Other info: LCD monitor calibrated with Spyder2 Pro

Comments: this was an HA-LRGB composite created from 2 versions. One was a DDP stretched HA-RGB to enhance background data; the second was an L-HA-RGB focused on the ring data. HA data was combined with the red channel for both versions. The 2 resulting final images were combined using a layer mask technique in Photoshop.