Total 2:45 hours 165 min. = L (9x10min.), RGB (5:4:6, 5 min. each)

Officina Stellare Riccardi-Honders Veloce 200 RH OTA
Officina Stellare - http://www.officinastellare.com/products_scheda.php?idProd=15
On my site - http://www.pbase.com/boren/officina_stellare_riccardihonders_veloce_rh_200
Deeper technical informaiton on the Riccardi-Honders design - http://www.telescope-optics.net/honders_camera.htm
SBIG ST8300M, LRGB Astrodon Gen II filters
NEQ6 mount, guided w/PHD

With an angular diameter of 2.9 arcmin., Abell 39 is a low surface brightness (Mean Surface Brightness: 24.6 Mag/arc-secē, and Integrated Visual Magnitude: 13.7) planetary nebula in the constellation of Hercules. It is the 39th entry in George Abell's 1966 Abell Catalog of Planetary Nebulae (and 27th in his 1955 catalog) of 86 old planetary nebulae which either Abell or Albert George Wilson discovered before August 1955 as part of the National Geographic Society - Palomar Observatory Sky Survey.

The nebula is estimated to be about 6,800 light-years from earth and 4,600 light-years above the Galactic plane. It is almost perfectly spherical and also one of the largest known spheres with a radius of about 2.5 light-years.

Its central star is slightly west of center by about 2" or 0.1 light-years. This offset does not appear to be due to interaction with the interstellar medium, but instead, it is hypothesized that a small asymmetric mass ejection has accelerated the central star. The mass of the central star is estimated to be about 0.61 solar masses; with the material in the planetary nebula comprising an additional 0.6 solar masses.

This planetary nebula has a nearly uniform spherical shell. However, the eastern limb of the nebula is 50% more luminous than the western limb. Additionally, irregularities in the surface brightness are seen across the face of the shell. The source of the east-west asymmetry is not known but it could be related to the offset of the central star.

The bright rim of the planetary nebula has an average thickness of about 10"; or about 0.34 light-years. This planetary nebula has been expanding for an estimated 22,100 based on an assumed expansion velocity between 32 and 37 km/s and a 0.78 parsec radius.

Oxygen is only about half as abundant in the nebula as it is in our own sun (ref. http://en.wikipedia.org/wiki/Abell_39)