M 20 - THE TRIFID NEBULA

Sagittarius

(ra: 18,02.6 / dec -23:02)

DATA

TYPE: Emission and Reflection Nebula

VISUAL BRIGHTNESS: 9

SIZE: 29 x 27 arcs minutes

DISTANCE: between 2200 and 6000 light years

OBJECT DESCRIPTION

M20 is one of the attractions of the southern winter sky. It can be easily seen with 7x50 binoculars  even in relatively light polluted skies.  Its name came out of the reddish three lobed appearance which are ionized from the central star HN 40, a sextuple star system. Charles messier described it as a cluster of stars of 8 to 9 magnitude surrounded by nebulosity in 1764.

IMAGE INFORMATION

SCOPE: Celestron SCT C8 at (roughly) f6.7

MOUNT Vixen GPDX mount with Sky Sensor 2000

SKY CONDITIONS: visual limit magnitude 4. Windy session

CAMERA: Starlight SXVF H9

FILTERS: Astronomik Type II, Ha 6nm, IDAS LPS II

EXPOSURES: LHaRGB (40,12,12,12,12) 120 seconds subs

GUIDING: Synta 70/400 Refractor. SXV Guide Head

IMAGE ACQUISITION: Astro Art and CCD Control Interface 3.72

CALIBRATED: ImagesPlus (no darks removed) Richardson Lucy Deconvolution PROCESSING: Photoshop CS