Today the outer giant planet Jupiter reaches the point in its orbit around the Sun that places the Earth in between Jupiter and the Sun. This is known as opposition, and opposition is an orbital position that applies to solar system objects (outer planets, dwarf planets, asteroids, comets, etc.) orbiting the Sun beyond the Earth’s orbit. An object at opposition will have approximately the same heliocentric longitude as the Earth’s heliocentric longitude – which today both have a heliocentric longitude of about 105o. When an object is at opposition it rises at approximately the same time as local sunset (see the banner graphic) and that same object at opposition sets at approximately the time of local sunrise. In other words an object at opposition will be up all night from sunrise to sunset.
Picture our Moon at full phase and how it is directly opposite the Sun, with the Earth in between. The full Moon in effect is at opposition but we call it the full Moon instead. And like Jupiter at opposition, a full Moon rises at sunset, sets at sunrise and is visible all night. January’s full Moon, by the way, is on the 16th.
Take a brief tour of the Jovian (Jupiter) system. Music by Dark Matter.
Live recording of music written by Richard Johnson. Video by me!
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.