May 9th, 2018: Jupiter

[xoxoxoBruce]

Got the secret hots for Jupiter? Dream of fondling that red dot? Then May is your month.

It takes the gas giant 12 years to wend its way around the sun. At this point in its orbit, it is at opposition—the position where it is closest to Earth, on the side farthest from the sun. (“Close” is relative, though: Even when Jupiter appears to be in our celestial neighborhood, it’s still 410 million miles from us.) Jupiter is among the brightest objects in the sky, and if you plan to attempt a close-up look at the planet this year, this week will yield particularly stunning views.

Got light pollution up the ying yang? Doesn’t matter much.
What does matter in obstructions on the horizon like buildings, hills, trees, and your Mom.

In a city, skyscrapers may limit your view until after midnight, when the planet rises above them. At its highest, Jupiter will be about 33° in altitude when it is due south, says Peter Tagatac, president of the Amateur Astronomers Association of New York. Using a body as a calculation device, 33° is roughly “three fists with capped thumb at arm distance above the horizon.” Jupiter will be most visible when it climbs 20° or greater above the horizon, says Tagatac. Today, that’s about 10 p.m. EST; as the month progresses, it will be a little earlier each day.

Through binoculars, Jupiter will appear as a slightly larger dot flanked by dimmer ones. These are four of its moons: Io, Europa, Ganymede, and Callisto. (Galileo, the first astronomer to record sightings of those moons, did so in 1610 with magnification 18.) Binoculars are ample enough to glimpse the moons, “but their drawback is that sometimes it’s hard to hold them still enough to enjoy the sight,” says Shana Tribiano, an associate at the Hayden Planetarium at the American Museum of Natural History. If you’re peering through binoculars, it might help to mount them.

But if you mount them my experience is they tend to get real shaky.

Details on the planet’s surface will emerge when you look through a small telescope with a magnification of 75 or 100 power. “The brownish equatorial bands stands out with a ruddy hue,” Tagatac says, and when a Jovian moon slinks between the Earth and Jupiter, a small telescope would suffice “to see its shadow transit like an inky black dot.” Some public libraries have telescopes available to borrow. If yours doesn’t, contact your a local astronomical society or club about public viewing hours.

Or mug an astronomer.

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