Viewing Venus at sunset
OVER the past few weeks, my morning and evening commutes along Otago Peninsula, have each offered some memorable views.
This time of year, my dawn departure from Portobello coincides with sunrise, which for a critical few minutes on still mornings, with low clouds, regularly transforms the harbour from a dull monochromatic scene into an astonishing fiery vermilion maelstrom, resembling the background in Edward Munch’s painting The Scream.
This vista is so engaging, I regularly have to pull over to try to photograph what I see, which often makes me late for work!
While not quite as spectacular as my outward trip, my return journey has been considerably enlivened by the appearance of the planet Venus. Each night, as the sky darkens, Earth’s closest planetary neighbour climbs slightly higher in the sky over the hills embracing Otago Harbour.
Because it is close to us, and because it is enshrouded by a thick noxious atmosphere, whose sulphuric acid clouds are highly reflective, Venus is by far the brightest planet. Wherever you live in Otago, if you have access to an unobstructed view towards the northwest, you should have absolutely no problem spotting it, low in the sky after sunset.
As our chart indicates, Venus is presently in the constellation of Gemini, close to the stars Pollux and Castor. Above Venus, the stars Procyon and Sirius complete a pretty triangle as twilight fades. Our chart is drawn for roughly an hour after the sun sets, at which time Venus will be almost 10 degrees above the horizon (that’s about the same angle as that subtended by your fist when held at arm’s length).
If you have a telescope, you can use it to study the tiny disc of Venus. Currently, the planet is approximately 80% illuminated, which means it resembles the moon halfway between first quarter and full. At the moment, Venus is 188 million km from Earth, meaning the light you see (which is actually sunlight reflected from the planet’s thick cloudy atmosphere) began its journey to your eyes just over 10min ago.