|
On June 8, 2004, an exceedingly rare celestial event occurred - the transit of the planet Venus across the
face of the sun as viewed from earth. This phenomenon is so rare that until June 8, it had not been witnessed by
any currently living human being - the last such transit occurred in 1882! This transit lasted over six hours,
and was visible in its entirety over much of Europe, Asia, Africa, and Australia.
Further west, only the last 90 minutes or so of the transit were visible in eastern North America, and it was
not visible at all in western North America as it started and completed overnight in that area.
This first picture below was taken just a few minutes after local sunrise (5:50 AM EDT) in Pittsburgh. At
the time the sun was dim enough in the morning haze that it could be viewed with the naked eye, and the large black spot in
the lower right quadrant of the solar disk was easily visible with no optical aid. All pictures were digiscoped
using a Nikon Coolpix 4500 handheld to a Leica 77-mm APO spotting scope - proof that birding gear can yield some pretty cool
results when applied to other pursuits!
Here, Venus is shown about fifty minutes after local sunrise, now much closer to the edge of the solar disk as it proceeded
across the face. By this time the sun was at full daytime brightness, and an ND-5 filter had to be applied to
the telescope for safe viewing, which reduces the sun's luminocity by a factor of 100,000!
Finally, the "egress" phase is shown here, where the Venusian disk comes in contact with the edge of the solar disk as
it completes its transit. (The time of first contact with the solar disk is called "ingress"; sadly, it was not visible
from the eastern US as it occurred around 1:30 AM local time.) This picture was taken about four minutes into the egress
(which itself lasted 20 minutes), nearly one hour and fifteen minutes after local sunrise. A spectacular show!
Transits of Venus come in pairs (eight years apart) about once every 120 years. If you missed this show, the next
chance will be in 2012. After that, another is not due until the twenty-second century!
Photos by Geoff Malosh
|
