M22 – SAGITTARIUS CLUSTER

Sagittarius

 (ra: 18,36.4 / dec -23:54)

April 2011, Laguna de Todos los Santos, Buenos Aires, Argentina

Collaboration with Juan Jose Destefani (acquisition) and Sergio Eguivar (processing)

DATA

TYPE: Globular Cluster

VISUAL BRIGHTNESS: 5.1

SIZE (apparent): 32 arcs minutes

DISTANCE: 10.400 light years

OBJECT DESCRIPTION

M22 is one of the closest globular clusters. Gathering around more that 100,000 stars it has a diameter which is bigger than the moon. Its brightness overpass M13, but it is outshined by Omega Centauri and 47 Tucanae. This was probably the first globular cluster ever discovered. For the observers M22 is at one degree of the elliptic, thus is very common to see this cluster in conjunction with other planes. In this respect it was discovered by German Amateur Astronomer Abraham Ihle when he was observing Saturn in the year 1665.

IMAGE INFORMATION

SCOPE: Orion ED 80  @ f7.5 with Sky Watche HEQ5

SKY CONDITIONS: Good  Transparency

CAMERA: Canon XSI unmodified

FILTERS: none

EXPOSURES: RGB 12 x  360 seconds subs

GUIDING: Orion Short Tube - Philips Toucam

CALIBRATED: Images Plus darks bias and flats used. Richardson Lucy Deconvolution. Photoshop CS