Jupiter is by far the largest planet in our solar system, at last count it was orbited by approximately 63 moons as of 2003. The largest of these moons are Ganymede, Io, Europa, and Callisto.
Jupiter derives its name from a Roman god, whom myths and legends have so graciously appointed as the king of the gods. The Greeks held Jupiter in high reverence also, but called him Zeus, but no matter what you call it Jupiter is by far one of the most magnificent planets observable through backyard telescopes.
Looking through the telescope at Jupiter, you will see a world that much reminds me of the shooter marbles we used to play with when we were kids – you know the ones-the big ones- that had all the beautiful swirls of different colors that seemed to dance inside the little translucent orbs we held in our hands. The ones that appeared to glow with pearlescent shades of blues and purples, mixed with the opalescent hues of green and almost faded pink. These are the colors one can expect to see set against the planets darker shades of the equatorial and temperate bands.
The Chemical Composition of Jupiter’s Clouds
When looking at Jupiter, the bright zones are composed of ammonia crystals which appear pure white. The orange and brown shades are caused by contaminates perhaps ammonium hydro-sulfide that well up from the lower cloud layers near the surface. The bluish markings are openings in the cloud layers where we can see deeper into the clear hydrogen / helium atmosphere. This blue appearance is caused by the incoming light being diffused through the gas mix.
When using colored filters to observe Jupiter, a light green Wratten 58 or a blue Wratten 80A filter will boost the contrast of Jupiter’s reddish brown markings. I also believe you will find that the yellow Wratten 12, and the light orange Wratten 15 will help in bringing out the subtle markings of the rather bland polar regions.
Jupiter’s Belts and Bright Zones
The bands which extend parallel to the planets equator are the defining lines that separate Jupiter’s equatorial region from the northern and southern tropic, and temperate zones. These bands consist of colors ranging from bluish white to light brown that fade to tan then to pale yellow. The regions of Jupiter are split into two distinct categories which are dark and bright anomalies. I have provided you with a short list of these anomalies in the hopes that you will find it useful.
Dark Belts
North Polar Region
North North temperate belt
North equatorial belt
Equatorial band (running dead center of the equator)
South equatorial belt
South temperate belt
South South temperate belt
South Polar Region
Bright Zones
North North Temperate Zone
North Temperate Zone
North tropical zone
Equatorial zone
South tropical zone
South Temperate Zone
South South Temperate Zone
This list is known as the Nomenclature of Jupiter. It is based on the correct terminology to be used for the climatic divisions on Jupiter’s surface. The wide band that you see in the telescope which is located about 6 degrees on either side of the equator is called (you guessed it) the Equatorial Zone. The equatorial zone is bordered on the upper and lower side by the North and South equatorial bands. On either side of the equatorial bands are the lighter in color North and South tropical zones. On either side of the north and south temperate zones are two more belts and zones known as the North and South temperate belts and two more zones. This set of belts and zones are pretty wide, in fact they cover about 70 degrees of the remaining surface, and fluctuate in their width from 32 to 36 degrees as they run in an east to west direction north or south of the planets equator.
The observations made through the telescope of the cloud layers will reveal features in the clouds that will manifest themselves as different shaped anomalies such as storms like the great red spot that has been raging now for hundreds of years, and has been joined as of late by the newest apparition the junior red spot which is slowly catching up to its larger brother and is expected to join up with it in the near future.
I have compiled a small list of these anomalies that might assist you in your observations.
Anomalies Seen on the Surface of Jupiter
Ovals
Ovals look like the great red spot only smaller. They occur in the belts and zones, and all ovals are storms on the surface.
White Spots
White spots are smaller and appear a lot rounder than ovals. In the telescope they will appear about as large as the shadows cast by Jupiter’s moons.
Festoons
Festoons are thin dark streaks that often appear as bluish in color. They will extend diagonally from a belt into a zone, and sometimes all the way to the other side.
Rifts
Rifts are bright lines inside of a belt appearing as streaks of discoloration within belts or zones.
Bars Rods Barges
These are particularly strange dark lines of material of varying shapes and sizes, usually found between the two dark equatorial bands.
Knots
These are large lumpy thickening’s found in any of the belts, but most common in the equatorial bands.
Storms
Of all the storms that appear on the surface of Jupiter the most famous is the Great Red Spot. This storm is usually located at around 20.5 degrees south of the planet’s equator, attached to the south equatorial band, and centered in the south tropical zone. It is a very large oval which covers an area of about 23,000 kilometers at its widest portion, which runs in a east to west direction, and at its narrowest portion it is approximately 12,800 kilometers running in a north to south direction.
These storms have been raging for centuries. They are the result of surface winds that can reach speeds upwards of thousands of miles per hour. The reason for these astonishing speeds is the fact that on Earth the winds are driven by the Sun, so when the Sun goes down the winds quite down. But here on Jupiter the planet radiates more heat than it absorbs from the Sun so the storms and winds go unabated. When observing these surface features in the telescope, you will notice that these features cross Jupiter’s surface in about two hours.
In view of what we have learned in this article, I hope that the next time you have the opportunity to look at Jupiter even if it is in nothing but a pair of binoculars, you will not miss the chance to see this great neighbor of ours, the lord of the planets, Jupiter.
