Crux, the Coalsack and Centaurus

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The Crux is well known as the Southern Cross (middle, below), a help for finding the difficult position of Southern celestial pole (out of field, on the left). A little above the constellation a dark patch interrupt the Milky Way, that's the Coalsack dark nebula. At the upper border, the two bright stars are Alpha (orange) and Beta (blue) Centaurus, and on the right border the yellow object is not a star but the brightest globular cluster of the sky: Omega Centauri.

Technical data
Optics Canon lens 50 mm f/1.8 mkII
Focal Length 50 mm
Focal Ratio f/4
Exposure Time 1h30m (single exp of 10 min)
CCD Canon EOS 5D with Baader filter
Sensitivity 800 ISO
Location Tivoli Farm (Namibia) at 1350 m height
25 August 2011, h20 UT
Mount Losmandy G11
Tracking none
Temperature and humidity T= +11°C, RH=27%
Sky brightness at zenith (with SQM-L) 21.69 mag/arcsec^2 (MW at zenith)
Notes This image is a collaborative effort of the Namibia 2011 expedition. Processing: Lorenzo Comolli. Images by: Lorenzo Comolli, Luigi Fontana, Giosuè Ghioldi, Emmanuele Sordini.

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