This week offers one of the better opportunities of the year to catch a glimpse of the solar system’s innermost world. Trapped in its small orbit, Mercury never strays far from the sun, meaning it is usually lost to the light of dawn or dusk. On Sunday, however, the planet reached its greatest western elongation, meaning it appeared at its greatest apparent distance from the sun in the morning sky.
The next few mornings offer one of the best opportunities this year for catching a glimpse of the planet as it steadily brightens, improving the contrast with the gathering dawn. An early start and an unobstructed view towards the east-north-east will be essential to making the sighting. The chart shows the view looking in this direction from London at 04.30 BST on Tuesday.
If your line of sight is free from obstructions, the planet will become visible about a handspan above the horizon some time between 04.30 and 05.00. Binoculars can help, but exercise caution: sunrise on Tuesday from London occurs at 05.28, so stop using binoculars well before this time to protect your eyesight.
As a bonus, Mars will be much easier to spot, higher and to the east.
