Jupiter  King of the Planets
Part Three: Advanced Observing

Above is a collage of some sketches I have made over the years. As you can see, the first ones (made in 1996) are rather crude. As I continued to observe I was able to see more features and draw them accurately. The Great Red Spot is visible in #s 3, 4 and 8. (# 8 is not shaded accurately). Good examples of festoons are shown in #s 5, 7, & 8 (including a loop festoon in #7 on the left). In sketch #1, two shadows are shown on the face of Jupiter, caused by the moons moving in front of them. One of these moons is represented by a circle on the right side. Sketch # 2 is the same scene drawn a few hours later. The two shadows (and the white oval above one of them) have moved, and a third shadow is now visible.


Sketching

Sketch whenever you can! Sketching forces you to concentrate on details and improves your observing prowess. Above is a good template for you to print out and make copies. You may notice that the circle is slightly oval; this is because Jupiter is slightly oblate (wider at the equator- kind of "squashed") You don't need any special tools another than an ordinary pencil for sketching! It's best to start with features near the equator and work your way out. If you are especially interested in sketching, visit the Association of Lunar and Planetary Observers (ALPO). Your sketches and timings can contribute to better understanding of Jupiter!

Dance of the Moons

As fascinating as is to observe Jupiter, following the eternal dance of its 4 Galilean moons is just as exciting. Using a 6 inch telescope or larger and high magnification (200x and above), it is actually possible to see the disk of the moons. Although tiny, only about an arcsecond across, each moon shows a plain disk, not just a point of light. In addition, the Galilean satellites have their own special "events". They cast shadows on Jupiter's disk; they transit across Jupiter's disk; they are "occulted"  by (they pass behind) Jupiter's disk, and they are eclipsed by Jupiter. For more information on these events and when to see them, visit the Jupiter Satellite Events page (this is an off-site link).

Please share your Jupiter observations with us!

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