By the end of the week, our closest celestial neighbour will be visible as a beautiful thin waning crescent, rising a few hours before dawn.
On Friday the moon will be just 7% illuminated. By then, the lunar motion as it orbits Earth will have carried it from Virgo through Scorpius and into the constellation Sagittarius. If you have an unobstructed view to the southeast, you should be able to see it just to the left of the distinctive "teapot" formed by some of the constellation’s brighter stars.
By 5am, the time this week’s chart is drawn, our home planet’s only natural satellite will be a fine sight some 13 degrees above the horizon. This is also a great chance to look for Earthshine, which is the name given by astronomers to the effect which lights up the non-directly illuminated part of the moon.
Earthshine is sunlight that has reflected off both Earth and moon before reaching your eyes.
Early-rising stargazers also get one of the first chances this year to spot Mercury. The solar system’s innermost planet should be visible as a pinky/white "star" roughly 11 degrees below the moon. Mercury will get easier to see later in the month, reaching its maximum elongation on January 30.
Finding Mercury will undoubtedly be a bit of a challenge. This is because it is quite low (it reaches an altitude of just over two degrees at 5am). However, if the sky is clear, anyone living on the Otago Peninsula with a view of the Southern Ocean will have no trouble finding this fascinating planet as it clears the horizon.
If you have a telescope, point it towards Mercury. You will see that the planet is a tiny crescent, with just over 33% of the planet's surface illuminated by the sun.
