The two innermost planets meet in the gathering evening twilight this week. Mercury and Venus never stray too far from the sun, particularly Mercury. While there are times when Venus can be seen in a fully dark sky, Mercury never remains visible past sunset.
This makes it a challenge to find, but this week Venus gets close enough to Mercury to act as a useful signpost. The chart shows the view looking west from London at 1830 GMT on 8 March, although the view will be similar all week.
No stars will be visible at this time but the brilliant light of Venus will be unmistakable at an altitude of about 16 degrees above the horizon. Mercury will be fainter, located just 10 degrees in altitude.
Venus will be almost 70 times brighter than Mercury, so don’t be surprised if it takes a little searching to find the second planet. It is fainter because, although it is closer to the sun, it is much smaller than Venus with less than half the diameter, and its surface is less than one-tenth as reflective.
The two planets will be virtually impossible to see with the naked eye from the southern hemisphere.
