Venus Only 3° Away from the Sun
Taken by Helio C. Vital on June 17, 2016 @
Rio de Janeiro, Brazil
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Camera Used: SONY DSC-HX300
Exposure Time: 1/2000
Aperture: f/8.0
ISO: 80
Date Taken: 2016:06:17 15:00:49
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Details:
During daytime Rayleigh (direct) scattering of sunlight is the overwhelmingly dominant source of light. Hence, particularly in the vicinity of the Sun, sky brightness is extremely high, practically ofuscating anything. The apparent surface brightness of the Sun is currently some 40 thousand times higher than that of Venus (m=-3.9). However, the surface brightness of the sky surrounding the Sun is about four orders of magnitude lower only one solar radius away, roughly matching that of Venus and it continues to drop fast with distance. Then It occurred to me that, by using appropriate magnifications, maybe I could get enough contrast to reveal Venus in some photos, considering that it was 3.0° away from the Sun (topocentric distance from Rio de Janeiro) according to Skychart predictions. The calculations situated the planet roughly 6 solar diameters due east and 1 due north, corresponding to azimuth of 81°. Then I used the LCD monitor of the camera to target the area of interest and gradually zoomed in, thus experimenting with increasing magnifications up to 150x. Very good atmospheric transparency and stability prevailed during the shots, taken with a Sony Cybershot DSC-HX300 HS camera (with no filter attached), between 18:00 and 18:03 UT. The photos were meticulously analyzed in search for a bright dot that would pinpoint Venus where Skychart had calculated. A prominent green-purple region (on the right) visible in the first two photos resulted from major internal reflections in the lenses. Indeed about 40% of the photos did show Venus. In 1/3 of them, one or two much less conspicuous dots were also found. They were outside the area of interest, closer to the Sun`s disc and positioned in other directions. Possibly, they were caused by the presence of dust or other sources of minor reflections in the light path. Finally, a Skychart simulation and Soho`s Lasco C3 image for 18:19 UT are compared in the last picture. No filter or telescope was used.
Photographer's website:
http://https://www.flickr.com/photos/98669508@N03/
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