Fri, 03 Mar 2017
Watch Venus approach the Sun
Venus and Mars (upper left) on 2 March. Photo by Robin Scagell
Venus has been an obvious sight in the western sky after sunset for the past few months, but it will soon disappear from our evening skies as it gets too close to the Sun to be seen. It is rapidly moving between us and the Sun, so its phase is narrowing down to a thin crescent, as shown at right. Even binoculars will show the phase. The crescent is easily visible with magnification 10 binoculars, and probably lower magnifications if you have good eyesight.
At the start of March, Venus is easily visible fairly high in the twilight sky from about 15 minutes after sunset, and remains visible for three hours. But by the third week of March it’ll be very low down in the bright sky just after sunset, so you’ll need a low horizon and a good clear sky to spot it. However, Mercury will be coming into the evening sky to replace it for a couple of weeks. On 20 March, Mercury will be just 10º to the left of Venus, making a good opportunity to view or photograph the two inner planets at the same time Binoculars will help to pick out the planets in the bright sky.
After about this date, Venus will be too close to the Sun to be observed easily. Should you try, wait until the Sun is safely below the horizon to avoid any risk of catching its potentially blinding light in binoculars or a telescope.
Mars is also still with us, above and to the left of Venus. It is moving away from Earth now, and is virtually on the opposite side of the Sun, so it is much fainter and much smaller in a telescope than it was last year. However, it is actually higher in the sky than it was a few months ago, so you may still be able to see markings on its surface with a medium-sized telescope if our atmosphere is steady.
Added by: Robin Scagell