A brilliant star in the sky after sunset is attracting a lot of attention. In fact, it is not a star at all but the bright planet Venus.
Venus is our closest planetary neighbour, lying between us and the Sun. It is making one of its regular evening showings, having passed through superior conjunction, on the far side of the Sun, on August 14, 2019.
Venus spent the previous months of 2019 in the morning sky. From locations south of the equator, it became a dazzling beacon, much higher above the eastern horizon than for observers in the northern hemisphere.
Now it is setting after the Sun and so looks like a brilliant star in the evening sky again.
Venus becomes so bright that it attracts the attention of people who don’t usually notice the sky, and it has often been mistaken for a UFO!
During October, 2019, bright Venus became increasingly visible as it moved away from the Sun. Again it was easier to spot from southern latitudes because the angle of its orbit to the horizon was steeper. It appeared quite high in the western sky during evening twilight, shining down brilliantly.
A splendid opportunity for southerly observers to see Venus and the innermost planet Mercury came in the closing days of October as they moved close together in the sky.
From northern latitudes, the plane of Venus’s orbit was then at a much shallower angle to the horizon, because it was passing through the southern constellations of the Zodiac. It appeared much lower in the sky and less easy to see unless you had a horizon unobstructed by hills, buildings, trees and cloud.
From mid-northern latitudes, such as Europe and much of the USA, Venus viewing became easier during December because the planet started to climb higher in the sky from night to night.
It climbed still higher during January 2020, in the constellation of Capricornus, when it became an obvious, brilliant jewel in the southwestern evening twilight. A highlight comes on January 28, when the crescent Moon lies close to Venus.
Venus can shine as brightly as -4, using the astronomer’s scale of magnitude, making it the brightest natural object in the sky after the Sun and the Moon.
That means it will come into view before any of the stars in the evening, and stays visible after stars have disappeared in the morning twilight. Indeed, under perfectly clear skies, Venus is bright enough to be seen in daylight.
Even a small telescope will reveal that Venus is not a point of light but has a measurable disk, and one which shows phases just like the Moon does. During the latter months of 2019 and in early 2020, Venus will still lie on the far side of its orbit, and will show as a small gibbous disk through a telescope.
Venus will gradually grow in size, as its phase reduces, and it will resemble a half moon by the late March, 2020, and it reaches its Greatest Elongation East on March 24th.
A particularly fine spectacle to observe will come from April 2nd to the 4th, as Venus passes through the star cluster known as the Pleiades, or Seven Sisters, in the constellation of Taurus. This will make for a splendid photo opportunity!
During April and May, as nights grow shorter in the northern hemisphere, Venus begins to close back in towards the Sun, resembling a crescent through a telescope. You will need a very good, clear horizon to see its close conjunction with Mercury on May 21st and 22nd.
Venus will leave the evening sky on June 3rd when it reaches inferior conjunction, when it lies roughly between the Sun and the Earth (though not directly in line). After that, Venus moves back into the morning sky.
Related: How to observe Venus
Related: Venus – our neighbour from hell
Venus’s phase can be seen even with binoculars when it is a crescent, but do NOT try to view it with binoculars while the Sun is above the horizon as an accidental view of the Sun through them could damage your eyesight.
You can never see Venus in a midnight sky because it never gets more than about 47° from the Sun. This means it can’t set more than about about 4 hours after the Sun or rise more than 4 hours before it when it is in the morning sky.
Twilight is a good time to look at Venus through a telescope. That is because it will appear less dazzling against the brighter sky than against a darker background.
You can photograph Venus easily thanks to its brightness. Choose a nice foreground, such as some trees silhouetted against the twilight sky, and even a snapshot camera or smartphone should be able to record it. Hold the camera, or phone, steady to avoid camera-shake. If you have one, a photographic tripod will be useful.
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