Marco Palmer, age 11, of Oaksdale, Washington, for his question:
How can I prove I saw Jupiter?
On January 26, Marco trained his telescope on the skies and focused it on a bright planet. His problem is to prove that what he saw was giant Jupiter. There are several ways to do this, even long after the glorious event. An expert can tell in a moment the name of each visible planet in the sky. But a beginner needs a few clues.
And, as usual, the best way is to come prepared.
Every young astronomer deserves a telescope plus a subscription to a heavenly magazine that charts the changing positions of the planets. These charts announced that a brilliant and unusual display of planets would appear in the morning skies through most of January 1971. Andy arose early to behold them and was not disappointed. Early in the month, every morning before dawn, three bright planets were arranged in a razzle dazzle triangle. Each had arisen before the sun and the glorious display appeared in the southeastern sky.
The three reigning Morning Stars could be distinguished from several brilliant true stars in this region of the sky. True stars twinkle, while planets shine with a steady stare. The most brilliant planet was golden Venus, placed a little below Mars, which rose two hours earlier. Each morning, their positions changed slightly. On the morning of the 26th, Venus was 12 times brighter than Jupiter and the two planets appeared merely a hairbreadth apart. With this information, one could locate and identify them even without a telescope.
Focusing a telescope can be tricky, especially when two celestial bodies are so close together. But in this case, a close up view can reveal which is which. In a telescope, golden Venus appears as a hazy, unmarked disk, but the face of Jupiter is full of character. Its flattened disk is wider at the bulging equator. From pole to pole we see a series of parallel bands of streaky lighter and darker tones. A really sharp telescope reveals the banded streaks in pearly grays and beauteous pastel colors. These markings are cloudy patterns in Jupiter's thick, turbulent atmosphere.
A telescope reveals no markings on the face of Venus. The face of Mars is a smooth, simple disk, though stronger telescopes reveal surface blotches. Saturn, like Jupiter, is a flattened disk, banded with streaky clouds. But only Saturn is circled with dazzling golden rings besides which it was not present in that morning sky, If the planet you saw was much dimmer than nearly dazzling Venus, chances are it was Jupiter. If your telescope had revealed its light and dark banded markings, then you can be sure.
It so happens that these two planets appeared very close to Neptune. However, most likely this distant planet was too dim to appear in your telescope, Its markings resemble Jupiter's, but Neptune is distinguished by a greenish glow. Another confusing object on the scene was the bright star Antares. But it appeared dimmer than either Venus or Jupiter and its face in the telescope is an unmarked spot of light.