All-Sky with Galactic Center at zenith

Mousover for labels. Click on the image for a higher resolution version.

This single image is able to show the entire sky, thanks to the truly dark sky of the Namibian savanna and to the absence of mountains. Only some small trees from the Tivoli farm are visible toward West. The Milky Way center is probably the most interesting region in the whole sky and from this latitude (-23°) it reaches zenith when the sky darkens, in late August. The Milky Way draws a line from North to South, while another line is drawn by the Zodiacal Light/Band/Gegenschein. They cross each other near the zenith.
Unfortunately for the amateurs that search the darkest SQM measurement, the sky is "bright" due to the huge brightness of Milky Way and Zodiacal Light. No better that 21.6 can be obtained in the darkest regions. You need to wait the Milky Way to set to look at a really dark sky... Here is the same shot taken 6 hours later.

Technical data
Optics Peleng 8 mm f/3.5
Focal Length 8 mm
Focal Ratio f/5.6
Exposure Time 40 min (single exposures of 10 min)
CCD Canon EOS 5D with Baader filter
Sensitivity 800 ISO
Location Tivoli Farm (Namibia) at 1350 m height
Date
28 August 2011
Mount Losmandy G11
Tracking none
Temperature and humidity T= +15°C, RH=27%
Sky brightness at zenith (with SQM-L) from 21.6 mag/arcsec^2 (bright because of the Milky Way 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.


HTML Editing and Publishing by Lorenzo Comolli. Email me at comolli@libero.it.
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