Tuesday marks a once-in-a-lifetime opportunity to watch a rare astronomical event high in the skies the transit of Venus across the face of the sun.
When Venus travels between the Earth and the sun, visible in Vancouver from roughly 2:45 to 9:30 on Tuesday June 5, it will carry with it historical, as well as celestial, significance.
Beginning in 1639 when the transit of Venus was first observed and recorded, it allowed early astronomers to give a sense of distance and size of objects in the solar system.
Nowadays we have radar and lasers ... and different ways of measuring distance to planets, but in the old days by measuring Venus size against the surface of the sun as it went across, (astronomers) were able to determine the actual size of Venus and of the sun, said Sherry Buttnor, with the Victoria Centre of the Royal Astronomical Society of Canada.
These were smart people. They didnt have all these computers and fancy stuff, but they were able to do that just by looking at the sun.
They were actually very, very close with their predictions.
The image of Venus against the sun was used to determine an accurate estimate of the scale of the solar system.
A transit of Venus is rare due to the differing orbital speeds and planes of Earth and Venus the next is in 2117. The transit has only been viewed seven times since Galileos invention of the telescope in 1609.
Its neat to watch these things unfold in front of your eyes because it gives you a sense of motion, said Buttnor, who will be photographing the transit from Metchosin. We really are orbiting the sun. Things are moving out there.
(Viewing this) is a once-in-a-lifetime thing.
Watch the transit
Viewing the sun though No. 14 or darker welders glass is generally considered safe, though the glass, if scratched or nicked, opens the viewer to permanent vision loss.
The safest viewing method is pinhole projection, achieved by filtering sunlight through a pinhole in a piece of cardboard onto another blank surface. The projection is remarkably clear and removes the threat of vision damage caused by staring at the sun.
It will take a little over six hours for Venus to make this historic crossing. The HR MacMillan Space Centre in Vancouver will be holding a viewing event on Tuesday, June 5 from 2:45 pm - 9:30 pm. Staff will be on hand to talk about the significance of the event as well as provide hands-on kids' activities.. In addition to telescopes fitted with solar filters, solar viewing glasses will be distributed to all those attending to ensure safe solar viewing.
Story from Saanich News, Black Press
