NGC 104 -  (aka 47 TUCANAE)

GLOBULAR CLUSTER IN TUCANA

(ra: 00h 24.1/ dec -72º 05')

December 2012, -  Camping La Porteña, Areco, Buenos Aires - Argentina

DATA

TYPE: Globular Cluster

APPARENT MAGNITUDE: 4.03

APPARENT DIAMETER: 40 arc minutes

DISTANCE:  13,400 light years

IMAGE INFORMATION

SCOPE: ORION OPTICS UK 6" f5 Newtonian

CAMERA: QSI 583 WS

GUIDING: LodeStar in Synta 70/400 refractor / PHD Guiding

FILTERS: Baader LRGB Set

SKY CONDITIONS: Rural Skies.

EXPOSURES: LRGB (60,30,30,30) - RGB bin 2x2

OBJECT DESCRIPTION AND IMAGE SESSION

NGC 104, better known as 47 Tucanae, is the second largest and second brightest globular cluster in the skies, outshone only by another southern globular, Omega Centauri (NGC 5139). As its name "47 Tucanae" indicates, this object was first catalogued as a star and numbered the 47th in Tucana. Although a conspicuous naked-eye object, it is situated so much south at its declination of -72 deg, that it was not discovered as a deepsky object before 1751, when Nicolas Louis Lacaille catalogued it in his list of southern objects. Next it was observed and catalogued by James Dunlop in 1826, and John Herschel in 1834.

The stars of 47 Tucanae are spread over a volume nearly 120 light years across. At their distance of 13,400 light years, they still cover an area of the sky of about the same apparent diameter as the full moon, about 30 minutes of arc. Globular cluster 47 Tucanae is approaching us at roughly 19 km/s.