Jupiter is now an unmistakable dazzling object moving retrograde among the stars of Leo. On March 8th the current apparition peaks when opposition is reached. On this day the "King of the planets" shines brightest for the year attaining its largest apparent size. Visible all night long Jupiter rises in the east at sunset, reaches its highest point in the sky around midnight before setting in the west at sunrise.
The largest of the 8 planets in the Solar System is currently located in southeastern Leo close to the Virgo border. With a declination of 6 degrees north it's best seen from equatorial and tropical latitudes although reasonably well placed from all accessible locations worldwide. From mid-latitude northern or southern locations Jupiter attains a respectable peak altitude of about 45 degrees during the middle of the night.
At opposition this year, Jupiter is located 4.435 AU (663.5 million kilometers or 412.3 million miles) from Earth. Although slightly further away than last year its apparent size is still an impressive 44.4 arc seconds. Of all planets only Venus - on rare occasions - displays a greater apparent size than Jupiter.
Popular 7x50 and 10x50 binoculars show a very small white or creamy coloured planetary disk without detail. Easily seen are Jupiter's four large Galilean moons (Io, Europa, Ganymede and Callisto) which continuously change position as they orbit the giant planet. Sometimes all four are visible at once but on occasions the satellites will be temporarily obstructed as they pass by the planetary disk.
Theoretically all four moons are bright enough to be seen with the naked eye but their close proximity too much brighter Jupiter makes this task virtually impossible. However, a few very keen eyed observers have managed to spot them without optical aid. For comparison, Io shines at magnitude +5.3, Europa magnitude +5.6, Ganymede magnitude +4.9 and Callisto at magnitude +6.0.
Through a telescope a wealth of Jupiter's surface details are visible. Even a small 60mm (2.4-inch) scope at medium/high magnifications will show a number of details including the great northern and southern equatorial belts. Keen eyed observers under good conditions may also be able to see shadow transits of the Galilean moons on the Jovian disk. A larger 100mm (4-inch) telescope reveals ample bright and dark spots and the Solar System's most famous storm "The Great Red Spot". This complex weather system has been observed for centuries but is now diminishing in size. In the late 1800's its diameter was estimated at 41,038 kilometres (25,500 miles). At the time of the twin Voyager space probes flybys in 1979 it had shrunk to 23,336 kilometres (14,500 miles) with recent measurements from Hubble Space telescope images putting it at 17,912 kilometres (11,130 miles). This is a far cry from two hundred years ago and one day it will probably disappear completely.
With a 200mm (8-inch) telescope or larger Jupiter is a spectacular sight with well defined features along with subtle markings, smaller belts, ovals and festoons visible in the cloud structure. Under good seeing it's possible to push scopes close to their maximum magnification limits. This is generally accepted to be 50x for every 25mm (1-inch) of aperture.
But as always whatever binoculars / telescope you are using or even just with the naked eye, Jupiter is a fantastic object to view especially around opposition time.
Jupiter Opposition 2016 Data Table
|Opposition Date||March 8, 2016|
|Distance from Earth (AU)||4.435|
|Distance from Earth (Million Kilometres)||663.5|
|Distance from Earth (Million Miles)||412.3|
|RA (J2000)||11h 18m 27s|
|DEC (J2000)||+06d 04m 22s|
|Apparent Diameter (arcsecs)||44.4|