You can’t miss the evening star at the moment. The planet Venus is shining brightly in the spring skies of 2023, and it will remain with us into the early summer. But this year it disappears more quickly than usual as seen from the UK and northern Europe in particular. So what’s going on?
At the moment, Venus is coming around in its orbit from the far side of the Sun. Its orbit is closer to the Sun than Earth’s, so it never moves far away from the Sun. Here’s a view that includes its orbit:
Throughout April and May, Venus moves farther away from the Sun as seen from Earth, and gets closer to Earth as it does so. On 4 June, it reaches its farthest point from the Sun, so looking at the diagram above you might think that it would be higher in the evening sky. However, the angle of the orbit to the horizon gets shallower, so Venus stays at about the same height in the evening sky until about the beginning of May, then it starts to sink into the twilight, measured with the Sun six degrees below the horizon in all cases. Those farther south than the UK will be able to track it for longer.
You might think that such a brilliant planet would be a fantastic sight through a telescope. But Venus hides her beauty behind a veil of clouds – and it’s those clouds that make her shine so brightly in our twilight sky. All you can see is the planet’s phase.
When people see Venus through a telescope for the first time, they often think they are looking at the Moon, because Venus shows phases just like those of the Moon. At the end of March, being beyond the Sun in its orbit, most of the planet is illuminated and it looks like a gibbous Moon. By the end of April, the phase becomes more obvious, and by 4 June the planet will look like a half Moon. All the time, as it gets closer to Earth, it gets larger and larger.
You can see these changes through even a small telescope, although it is quite tiny compared with a planet such as Jupiter. Try to view the planet while it’s still high up, in the twilight sky, otherwise it will be so bright that you’ll find it hard to see the phase at all!
By mid July, Venus is so low in the sky and close to the Sun that it can’t be seen from the UK in twilight, and we won’t be able to see it at its crescent phase. Those in the southern hemisphere will get a much better view. So make the most of viewing Venus this spring!