What's Up in Space
This Weekend’s Night Sky (23-24 May 2015)
Saturn reaches opposition this weekend, on the 23rd of May, when it will be at its closest and brightest in the sky, and high in the north at midnight. Saturn is now just 1340 million km and is particularly good for observing, with its rings almost at maximum tilt, but you’ll still need a small telescope to see them. It is rising in the east at the beginning of the night, officially in the constellation of Libra, but lying very close to the line of three stars marking the pincers of Scorpius, with the bright orange star Antares a little further to the right.
For a few hours around the time of opposition, you may see the rings brightening compared to the planet. This is because at the time of opposition the ice particles in the rings are illuminated from almost exactly the same direction from which we are observing them and therefor very few of them are in shadow. This is known as the Seeliger Effect.
On Sunday comet C/2015 G2 (MASTER) is at perihelion, making its closest approach to the Sun at just 0.78 AU, and is currently at magnitude 7.6.
Also look out for a beautiful conjunction of Jupiter with the crescent Moon on Sunday. The two will be just 4°58' apart in our northern skies after dusk, with Jupiter coming in to view as the twilight fades.