MESSIER 7 - OPEN CLUSTER

Scorpious

(ra: 17,53.9 / dec -34º:49')

July 2011,  Los Molinos - Córdoba, Argentina

DATA

TYPE: Open Cluster

VISUAL BRIGHTNESS: 3.3

SIZE (apparent): 80 arcs minutes

DISTANCE: 800 light years

OBJECT DESCRIPTION

M7 is also known as the Ptolemy's Cluster after Greek astronomer Claudius Ptolemaeus mention by 130 AD. M7 is one of the brightest cluster of the sky. It can be seen even from urban cities and also a good target for binoculars and small telescopes. From my backyard in good nights and with some effort it can be seen with the naked eye. The cluster contain some 80 stars with a magnitude range from 7 to 12. It is quite close from the centre of our Milky Way therefore the background field full of stars. M7 with its declination -34 º 49 is the southern object of the Messier list.

IMAGE INFORMATION

SCOPE: TMB 92 @ f5,5

MOUNT: NEQ6 SW

GUIDING: Orion 80/400 refractor with Starlight Xpress LodeStar AstroArt 3.0 - Control Interface 3.72 plug in

CAMERA: QSI 583 WS

FILTERS: Baader LRGB

EXPOSURES: LRGB (30,30,30,30) 

IMAGE ACQUISITION: Astro Art and CCD Control Interface 3.72

CALIBRATED: Images Plus. Photoshop CS