Under the Southern Cross


I’m back home in Canada now, after 24 hours of travel from Chile. Despite having to check my carry-on bag filled with cameras and the Mac laptop for the Calama to Santiago domestic flight, all the gear arrived home intact. Now to process the 40+ gigs of images I shot. And properly reprocess some of the images worked on at the dining room table at the lodge, under the bright Chilean sun.

Here’s a shot taken the last night of shooting, of the icon of the southern sky, the Southern Cross, more formally called the constellation of Crux. Next to it, at left, are the dark clouds of the Coal Sack. To the eye, these clouds looks like a uniform dark spot in the sky. But photos, and even binoculars, reveal it as a complex mess of shapes and densities.

What stands out are the colours of the Cross stars. Most are hot blue Type B stars – energetic blue giants. But Gacrux at top is very red – it’s a cool red giant star.

Scattered amid the Cross are Coal Sack are several clumps of stars – open star clusters, such as the Jewel Box Cluster to the left and just below Becrux, the left star of the Cross. On our final night at the Atacama Lodge, we helped out at the lodge in a public stargazing session to a group of tourists from all over the world. I ran a telescope aimed at the Jewel Box and heard lots of ooohs and aaahs at the sight of its multicoloured stars.

This shot is a Mean-combine stack of five 3-minute exposures at f/2.8 with the wonderful Canon L-series 135mm telephoto, and the Canon 5D MkII camera, filter-modified, at ISO 800. The camera was on a Kenko SkyMemo tracking platform, which followed the stars during the 15 minutes worth of exposures.

– Alan, May 9, 2011 / Image © 2011 Alan Dyer

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