Starwatch: Mercury reaches greatest western elongation

As this elusive inner planet orbits its furthest from the sun westwards, it will be visible in the morning sky

Get your Christmas started with a celestial achievement by tracking down the inner planet Mercury early in the morning.

Because of its tight orbit, Mercury never appears far from the sun. This makes it a challenging object to observe because it never appears in a fully dark sky, only close to the horizon during twilight.