Animation of Venus' Shadow

January 22, 2011

Photographer: Vincent Jacques; Vincent's webpage
Summary Author: Vincent Jacques; Jim Foster

The animation above shows my telescope's shadow as cast by Venus' reflected light on a wall outside of my home in Breil-sur-Roya, France. Next to the Moon, Venus is the brightest object in the night sky, and on the morning of January 12, 2011, it blazed away at a magnitude of -4.4. If you are in a dark location with no artificial lighting, Venus is indeed bright enough to cast a dim but unmistakable shadow. Can you detect the subtle change in shadowing on the wall? These shadow bands evidently result because of scintillation when Venus is fairly close to the horizon. The small fluctuations in density in the lower portion of the troposphere make objects (most often stars) appear to twinkle. Therefore, it is the twinkling that causes the shadow bands. Note also the bright trace of an artificial satellite on one of the frames.

Photo details: Each frame of the animation was taken with a Canon EOS 350D camera; a 18mm lens; f/D=3.5; at 1600 ISO. Photos imaged at approximately 5:00 a.m. before astronomical twilight.