What’s in the Sky: May

Jupiter enters the evening sky in May and will make its closest approach to Earth in 2018 on May 8. The solar system’s giant will be “only” about 409 million miles distant. If you could drive there at 70 mph, it’d take you almost 667 years! At a commercial jet speed of 500 mph, you might make it in a lifetime – over 93 years. The fastest time by an Apollo Moon mission was Apollo 10, traveling over 24,700 mph. You’d make it in a bit under 2 years. The solar system is immense!

Look for Jupiter low in the southeast after sunset. It will be located in the dim constellation Libra. It will rise higher in the sky during the month, finishing May almost due south at 11:30 p.m. It will be easy to pick out, as the planet will outshine all nearby stars. You may notice that it does not twinkle as much as nearby stars.

Planets are close enough that we get more light from them than we do stars, even though they are much smaller than the stars. The small amount of light we get from stars is refracted by our atmosphere, causing them to twinkle, especially stars near the horizon. Planets shine more steadily, a good clue when looking for them.

Jupiter is a great sight in a telescope. The disk is relatively large and easy to see, and you can usually make out bands of clouds in its atmosphere. Its 4 largest moons are also easily visible, as pinpoints of light along the planet’s equator.

As the moons orbit Jupiter, they change position each night. Even if you don’t have a telescope, a good pair of binoculars will also show the moons. Give it a try, and watch the moons change relative position from night tonight.

Earth’s Moon will be full on May 15 and full on May 29. If you are up early, look for the Moon to the right of Saturn on May 4, and between Saturn and Mars on May 5. Look due south before sunrise to catch them. On May 17, the thin crescent Moon will be low in the evening sky after sunset, just to the left of bright Venus.

Venus will shine brightly for the entire month as the “evening star,” visible after sunset. Saturn and Mars will still be morning objects in May. By the end of the month, Saturn will be rising around midnight. More about them in future months!

A couple of constellations rising in the east during May are Hercules and Lyra, harp. Lyra is a small constellation but contains the 5th brightest star in our sky, Vega. Look for it low in the east-northeast after dark.

Hercules is a bit more difficult – it lies just above and to the right of Vega. Hercules’ four brightest stars make up a shape called the “Keystone.” It is about 1/3 of the distance between Vega and Arcturus, the bright star in Boötes, which will be high in the southeast.

Hercules contains my favorite object to view, the Hercules Globular Star Cluster, located along the upper edge of the keystone. The cluster is made up of some 300,000 stars, packed in a relatively small area of space. Through a telescope on a dark night, it dazzles like a diamond. It is a great object to view in a telescope and can also be seen in binoculars as a fuzzy “star.”

Use the picture accompanying this article to locate it. It is a great object to view through one of Goldendale Observatory’s portable telescopes at their temporary home next to the Stonehenge replica south of Goldendale.

Enjoy May’s night skies!