reactions between methane and nitrogen. Most prominent was a huge snow-white heart shape, formed from
fresh deposits of nitrogen ice. It’s been named, appropriately, after Pluto’s discoverer: Tombaugh Regio.
The night sky at around 10 pm this month
(Nigel Henbest)What’s Up
The first thing you’ll see after sunset is the glorious Evening Star over the west: Venus is more brilliant than
all the stars and other planets, and by the end of the month it’s not setting until after midnight. On 28
March, the crescent Moon forms a stunning pair with Venus.
As the winter constellations, like Orion, begin to sink down towards the west, we are treated to the star
patterns of spring. The familiar seven stars of the Plough, part of the larger constellation of Ursa Major (the
Great Bear) lie almost overhead. High in the south crouches the celestial lion, Leo, his heart marked by the
bright star Regulus. And below Leo is the long straggly shape of Hydra, the water snake – the largest
constellation in the sky, though made up of some pretty faint stars. Its brightest member, in a region devoid
of anything much else, is called Alphard – appropriately meaning “the lonely one”.
There’s a lot of planetary action going on in the early morning sky, with three planets performing a stately
dance. Most brilliant is Jupiter, now rising around 4am. To its left is Saturn, some ten times fainter. The
Moon is nearby on the mornings of 18 and 19 March. At the start of the month, you’ll find Mars (similar to
Saturn in brightness) lying to the right of Jupiter; but the Red Planet is steadily moving leftwards, passing
just under Jupiter on 20 March and below Saturn on 31 March.
If you have a moderate telescope, there’s a rare chance to easily locate the faint dwarf planet Pluto, as Mars
passes right past the distant world. On the morning of 23 March, around 5am, point your telescope to the
Red Planet on high magnification, and the faint “star” nearby is remote Pluto.
Diary
7 March: Moon near Regulus
8 March: Moon near Regulus