Messier 55 (NGC6809) is a globular cluster in the constellation of Sagittarius.. It was discovered by Nicolas Louis Lacaille 1752 while observing from South Africa. Charles Mesiier made several attempts to find this object from Paris, France, but the low declination meant it never rose sufficiently far above the horizon to allow for easy observation. He finally observed and catalogued it in 1778. The cluster can be seen with a pair of 50 mm binoculars, although resolving the individual stars requires a medium-sized telescope.
M55 is at a distance of about 17,600 light years
RA: 19h 39m 59.40s Dekl.:−30° 57′ 43.5″ Apparent size: 19 arcmin.
Image details: L = 8x1200s RGB = 8x1200s each
80cm f/7 ASTROOPTIK Keller corrected cassegrain, FLI Proline 16803, Baader LRGB-filters, Promt7, CTIO/UNC Chile
Image processing:Bernd Flach-Wilken
below is a 80% cropped image field: