Stargazers around the world focused on our local star, the
sun, last Tuesday (5 June) to witness a rare celestial event. The planet Venus
was silhouetted as it passed in front of the sun – the transit of Venus – and
this won’t happen again for another 105 years, until December 2117.
The transit was due to begin just after midday (local time)
and to end at about 6.43pm (although that wouldn’t have been visible here
because sunset on Rarotonga was at five past six). But in the morning it looked
as though nobody would see anything as thick clouds covered the island. There
were even a couple of brief showers.
We got the camera set up anyway. It’s not particularly fancy;
a point-and-shoot superzoom (Nikon Coolpix 500). We already had a solar filter
left over from the 2010 total eclipse.
When cameras like this are zoomed to the max, the lens
barrel extends out an extra 5cm from the body so we chopped up a plastic water
bottle, painted it black and attached it to the camera and the filter using
duct tape. The diameter was perfect and I guess it’s a different way to reduce
waste!
As noon approached the weather began to brighten up and by
the time the transit started the sky was clear, at least in the area around the
sun.
Our set-up wasn’t sophisticated. The camera was on a tripod
and every now and again we took a picture setting the focus manually on
infinity, and exposing at 1/500 sec at f8. As the sun tracked across the sky we
panned the camera to follow it. We drained several batteries and had to remove
the camera to replace them and at five o’clock, when the sun was about to
disappear behind some trees we upped sticks and headed to Nikao beach to finish
off. That’s why the video is somewhat jerky! But, hey, it was totally awesome
being able to see it.
The video is made up from about 120 still frames speeded up
to last ten seconds as opposed to the actual five and a half hours the transit
took.
What made things even better was the amount of interest it
generated locally.
My husband Phil wrote an article for Cook Islands News
before the event (Transit of Venus)
and teachers in Rarotonga and Mangaia took the opportunity to introduce
students to the thrill of astronomy.
In Mangaia the kids were able to watch using eclipse glasses
left over from 2010 (the solar eclipse was total on that island) and at Tereora
and Nukutere colleges on Rarotonga the heads of science Des Duthie and Russell
Grieve used their own telescopes to set up projected images so students could
view the historic occasion. (See Cook Islands News coverage here.)
