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Mike Kristosik

Our solar system’s largest planet, the gas giant Jupiter, will be at opposition on June 10.

This means that Earth is between Jupiter and the sun. It also means that Jupiter is closest to Earth.

On the night of June 10, Jupiter will rise at sunset in the southeast and be up all night long. The mighty planet will be big and bright for the entire month. The king of planets will shine at magnitude -2.6 (very bright!) and appear quite large in a telescope. It will reach its highest point in the sky about midnight.

Jupiter is the fifth planet from the sun. It masses one-thousandth that of the sun, but two-and-a-half times the mass of all of the other solar system planets combined. Seven spacecraft have flown by and two were sent to orbit it (Galileo in 1995 and Juno, which is currently orbiting).

The planet is a wonderful sight even in a small telescope. Immediately obvious are two dark bands, slightly ruddy or perhaps beige in the eyepiece. These are the N and S equatorial belts. There is a great deal of turbulence along the boundary of these belts that causes their edges to be uneven. In a pocket between the S equatorial belt and the S tropical zone is the famous Great Red Spot (GRS).

This is a persistent storm that has been known since at least 1831 and possibly since 1665. This storm is so large that the Earth could fit inside it. You’ll need at least a 6 inch telescope to see it. It has been recently noticed, by amateur astronomers, that the Great Red Spot is shrinking in size. This shrinking appears to be accelerating. Is it possible that the GRS will disappear in our lifetime? A cool thing about Jupiter is that our view of it changes quickly since one revolution of the planet takes just under 10 hours. So wait a bit and you could see different features in the same night.

Another cool thing about observing Jupiter are the four Galilean satellites. These satellites are named so because Galileo was the first to record seeing them (in 1610). They are from the interior outward; Io, Europa, Ganymede and Callisto.

It is fascinating to watch these worlds change position relative to Jupiter during the night and over several nights. If you are lucky, you might even see them cast a shadow onto Jupiter’s cloud tops as these moons pass between it and the sun.

Io is famous for its large scale volcanism. Huge plumes of volcanic gases (mostly sulfur) were seen by the Voyager spacecraft. Europa is thought to have a liquid ocean miles below its frozen surface. Sky and Telescope magazine (or skyandtelescope.com) is a great resource to access for information about Jupiter and Jupiter’s moons.

Another noteworthy planetary opposition coming up; Saturn, the beautiful ringed planet, will be at opposition on July 9.

Resource: HVA club

The Heart of the Valley Astronomers is a group of amateur astronomers dedicated to sharing our passion for the sky with the local community. We meet on the second Tuesday of each month (next: 7 p.m. Monday, June 11) at the Walnut Community Room, 4950 NW Fair Oaks Drive, Corvallis. Meetings are free and open to everyone. For more information, see www.hvaastronomy.com, or visit us on Facebook.

Astronomy Question of the Month

Which constellation harbors the center of the Milky Way Galaxy?

Answer to last month’s question: This year marks the 50th anniversary of what amazing event?

The Apollo 11 moon landing on July 20, 1969! Where were you when Neil Armstrong and “Buzz” Aldrin walked on the moon?

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Mike Kristosik is on the board of directors of Heart of the Valley Astronomers.