|STEP 1: The Canvas|
Jupiter's statistics boggle the mind: 318 Earth masses; 11 Earth diameters in size; one day is just 10 hours long. That something so large could complete an axial rotation in such a short time, is really amazing to me. Since Jupiter is a gas giant, his great rotational speed causes the planet to flatten slightly and appear as an oblate spheroid. My Jupiter template is about 3.25-inches by 3-inches in size, closely approximating Jove's 1.07 to 1.00 ratio of equatorial to polar diameter.
|STEP 2: Primary Features|
Of course, there are no surface features to be seen when observing Jupiter. Its atmosphere is just too dense to allow visible light to penetrate that far. And even if we could see thousands of miles into the Jovian atmosphere, there is no surface to see. Despite all the visible Jovian phenomena being atmospheric in nature, there are features which have been around long enough to have been named. Unquestionably, the best-known of these is the Great Red Spot. This huge anticyclonic storm has been observed for over 150 years. To give you a sense of its size, nearly three Earths could fit side-by-side across the Great Red Spot, which is visible as a large oval in my sketch. Other visible features include the polar regions, the north temperate belt and both equatorial belts. It's important to learn the standard nomenclature for planetary features. Knowing these names allow you to have meaningful conversations with others about your observations.
|STEP 3: Details|
Jupiter's atmosphere is typically teaming with detail. White ovals occupy the latitudes immediately south of the Great Red Spot (GRS). A cluster of three are visible to the right of the GRS in my sketch. Also, notice the disorganized appearance of the south equatorial belt to the right of the GRS. A series of festoons reach from the southern edge of the north equatorial belt (NEB) to the equatorial belt. Shallow depressions called bays are positioned along the southern edge of the NEB between the festoons. These are just some details commonly seen when observing the Solar System's largest planet.
|STEP 4: Finishing|
Since Jupiter rotates so quickly, it is a good idea to finish a sketch within a fairly short time frame, perhaps 30 minutes at the most. Otherwise, by the time you're ready to put the finishing touches on the drawing, you'll start to see new features which weren't there 45 minutes ago. I finish Jupiter sketches in much the same way as any other sketch. I rub in the pencil to soften the features. An eraser creates rifts through the dark NEB. The north temperate belt is darkened to match its prominence in the eyepiece. The polar regions are rubbed and rubbed until they have a dull grey tone. The final result is a deeply textured rendering, which captures much of the complexity of the Jovian atmosphere.
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Revised: June 15, 2003 [WDF]