The planets
JUPITER
BEST TIME IN FEBRUARY: 6 February, 00:30 UT ALTITUDE: 53º LOCATION: Cancer DIRECTION: South RECOMMENDED EQUIPMENT: 3-inch or larger scope FEATURES OF INTEREST: Atmospheric features, Great Red Spot, Galilean Moons
THERE’S NO MISTAKING magnificent Jupiter this month as the planet comes to opposition on 6 February, a time when it’s opposite the Sun in the sky. When this happens, Jupiter’s apparent diameter reaches its largest value for the year, which for 2015 is 45.3 arcseconds. It’s also at its brightest, shining away at mag. –2.6. Although opposition occurs on the 6th, through a telescope the view of the planet is optimal for a number of weeks either side of this date.
A small telescope will show plenty of detail on Jupiter’s disc. The most obvious features are the two dark belts that run north and south of the equator, known as the South Equatorial Belt (SEB) and North Equatorial Belt (NEB). The region between them is often filled with interesting features such as festoons. These typically appear as blue-grey swirls of material, draped into the equatorial zone.
Dark elongated barges and spots may also be seen with a 6-inch or larger scope. The famous Great Red Spot is somewhat easier. Nestled into the southern edge of the SEB, it can be glimpsed under steady conditions with a 4-inch telescope.
Other belts and features outside of the equatorial region can be seen, but these are often harder to pick out. The trick here is to really let your eyes get used to the scene. Use as high a magnification as the conditions will stand. A big, fuzzy planet is yields less detail than a small but steadier looking one.
The planet currently sits on the line joining mag. +1.4 Regulus (Alpha ( ) Leonis) to the Beehive Cluster, M44 in Cancer. At the start of the month, it is located roughly halfway along this line, but moves westward towards M44 as the month progresses. A full Moon sits 6º south of Jupiter on the 3rd.