05/09/2017 – Ephemeris – Looking at Jupiter through a telescope

Ephemeris for Tuesday, May 9th.  The Sun rises at 6:21.  It’ll be up for 14 hours and 35 minutes, setting at 8:57.  The Moon, 1 day before full, will set at 6:36 tomorrow morning.

The first thing one sees by turning a telescope to the planet Jupiter are it’s moons, that change position night to night.  A closer look at the planet itself will reveal that it is not exactly circular, but a bit squashed, making Jupiter fatter in the direction of the line of moons.  Jupiter has only a 3 degree axial tilt, and its four large moons orbit over Jupiter’s equator, so even though they have nearly circular orbits, appear to move back and forth in a straight line.  On the face of the planet itself appear parallel cloud bands of cream and reddish-brown.  The parallel cloud bands and the squashed appearance of the planet have the same cause.  Jupiter, though over a thousand times the Earth’s volume rotates, that is has a day, of a bit less than 10 hours.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

A slightly squished Jupiter with its Great Red Spot November 18, 2012 by Scott Anttila.

Overexposed Jupiter and its moons. Note the moon that looks like a bump on the left edge of the planet.  My archival image.