Jupiter's Great Red Spot - Drawings
Drawings of Jupiter's Great Red Spot Showing Belt, Zone and Festoon Detail
These detailed drawings of the Great Red Spot on Jupiter made
at the f/20 focus of the 16-inch reflecting
telescope under various magnifications using several Clave Plossl eyepieces were made on November 11
and 12, 1963. The 'seeing' and 'transparency' conditions were far better on the second night, and thus the
detail shown is much more extensive. It must be noted that the second drawing was made independent
of the first drawing, although some recollections of specific detail must have remained in my mind. The
detail of the 'line' festoon in the upper right does show a marked lengthening due to the cloud velocities
after about 20 hours. Because of the rapid rotation of Jupiter, all such drawings are made in 10 minutes
or less, otherwise rotational changes affect the accuracy of detail shown. South is at the top, east to the
A pencil sketch is made of the positions of belts (dark horizontal
areas) and zones (light horizontal
areas) prior to adding the fine details of structures and colors. Although no two people have the exact
same color sensitivity, I used many of the color photographs to reference the colors I choose. The
final drawing was then made at the desk the next day using general lighting from the outside to simulate
similar sunlight conditions, rather than a tungsten lamp. The reproduction of this original drawing using a
scanner, and then onto the Web page from an image editor is fairly close to the original.
It should be understood that what is drawn represents the best interpretation of the visual impressions
I was able to discern under the atmospheric clarity (transparency) and air turbulence (seeing) at the time.
Table Mountain Observatory, operated by the Jet Propulsion Laboratory (JPL), is located just west of the
town of Wrightwood, California at an elevation of 7500 feet.
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