TRUMPLER 20

 OPEN CLUSTER IN CRUX (THE SOUTHERN CROSS)    

(Image centered at: ra 12 h:41 m / dec - 60º 43')

March 2022, Home Backyard in Martinez, Buenos Aires, Argentina

DATA

TYPE: Open Cluster

APPARENT DIAMETER: 16 arc minutes 

APPARENT MAGNITUDE (V): 10.1

DISTANCE: 10,700 light years (around 3300 parcecs)

IMAGE INFORMATION

INSTRUMENT: 6" ORION OPTICS UK (Ultra Grade Optics) w/Sky Watcher Coma Corrector (0.9x) working at at f4.5

CAMERA: QSI 583 WS

MOUNT: SKY WATCHER NEQ6, OAG with Starlight Xpress Lodestar

FILTERS: Baader LRGB Set

SKY CONDITIONS: urban skies - Bortle 8

EXPOSURES: LRGB (40,40,40,40)

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OBJECT DESCRIPTION AND IMAGE SESSION

Trumpler 20 is a very rich open cluster, containing at least 700 members. It is located within the Southern Cross a bit more of one degree to the south from Beta Crux (the eastern arm). The cluster is compose by very faint members scattered over 16 arc minutes. It was discovered by American Astronomer Robert Julius Trumpler in 1930. The open cluster appears to have a significant reddening indicating an old age.