Physics Photo of the Week
September 7, 2012
Transit of Venus
On
June 5, 2012, soon after the 2012 Commencement at Warren
Wilson College, much of the world was able to view the last
transit of Venus across the Sun until December 2117 - more
than 105 years from now.
I photographed this event from the Craggy Visitors
Center at an elevation of 5500 feet with the help of my wife
Vicki, and WWC alumnus Gary Starkweather and his wife Vandy
- both avid amateur astronomers.
Venus transits are extremely rare due to the orbital
inclination of Venus' orbit (3.4 degrees relative to Earth's
orbit) and the relative closeness of Venus to Earth that the
angular separation between Venus and the Sun at the
conjunction is often highly magnified. Venus, about
the size of the Earth, appears relatively large also because
it is so much closer to Earth than the Sun. If Earth
and Venus were the same distance as the Sun, they each would
appear significantly smaller than the sunspots visible on
June 5 - about 1/100 the diameter of the Sun. The June
5, 2012 event was only the sevent
h recorded Venus transit
in over 400 years of telescope observations and only the 4th
Venus transit that was photographically recorded.
However, with the rapid development and availability of
digital cameras, the 2012 transit is estimated to have been
photographed by over 20,000 amateur and professional
astronomers throughout the world.
The above image is only one of several hundred images
taken with a 3 1/2 inch Questar telescope (donated to WWC by
Ralph Brown of Chattanooga, TN) and a digital camera.
Some have been made into a time lapse video clip shown at
right. The frames for the sequence were recorded once
a minute and played back at 33 times a second. This
playback speed is almost 2000 times the original
speed.
Also shown below is the final image just before sunset
where Venus' silhouette can barely be seen between clouds
near the horizon - about 1/3 across the Sun from the
top. The final image was taken with a "standard" zoom
telephoto lens with no filter other than the extensive
Earth's atmosphere at the horizon. The other photo (by
Gary Starkweather) shows several other amateur astronomers
and onlookers at the Craggy Visitors Center.
Physics Photo of the Week is published weekly during
the academic year on Fridays by the Warren Wilson College Physics
Department. These photos feature interesting phenomena
in the world around us. Students, faculty, and others
are invited to submit digital (or film) photographs for
publication and explanation. Atmospheric phenomena are
especially welcome. Please send any photos to
dcollins@warren-wilson.edu.
All photos and discussions are copyright by Donald Collins or by the person credited for the photo and/or discussion. These photos and discussions may be used for private individual use or educational use. Any commercial use without written permission of the photoprovider is forbidden.
Click here to see the Physics Photo of the Week Archive.
