PICK OF THE MONTH
JUPITER
BEST TIME TO SEE: 31 January, 06:00 UT ALTITUDE: 19º LOCATION: Libra DIRECTION: South-southeast FEATURES: Complex atmosphere, Great Red Spot, Galilean moons EQUIPMENT: 3-inch or larger scope
Jupiter is in Libra and a morning object. It fails to reach its peak altitude at the start of January, but just about manages it in the slowly brightening skies at the end of the month.
The start of 2018 sees Jupiter and Mars very close together in the morning sky. Jupiter shines at mag. –1.7 on 1 January with Mars significantly dimmer at mag. +1.5. Both planets appear close to mag. +2.8 Zubenelgenubi (Alpha (_) Librae) on New Year’s morning.
The real close encounter, however, occurs on the mornings of 6 and 7 January. On 6 January, Mars appears 24 arcminutes southwest of Jupiter. If you can catch them soon after they have risen on 7 January – say from around 04:00 UT – they will appear around 13 arcminutes apart. This should present a good opportunity to photograph both worlds through a telescope, catching orange Mars and Jupiter, together with its Galilean moons, in the same frame. On the morning of 7 January, Europa and Io are located just east of Jupiter, with Ganymede and Callisto much farther away to the west of the planet.
A waning crescent Moon joins the scene on the morning of 11 January. On this date the 28%-lit lunar crescent sits to the north of both planets. At the end of January Jupiter will appear more centrally postioned within Libra and slightly brighter at mag. –1.8. Through a telescope its oblate disc currently appears 35 arcseconds across. A small telescope will show both the North and South Equatorial Belts, located either side of the planet’s equator. With concentration, a 4-inch telescope will show the planet’s most famous feature, the Great Red Spot. Some good interactions between Jupiter and its moons will be visible this month and the best of these are listed on pages 50 and 52.