Gateway to the Stars June 7: A Big Dipper Star Hop

Mike Murray

This is the time of year when the familiar stars of the Big Dipper are highest in the north, which makes this group an excellent guidepost to other stars and Deep Sky Objects.

How can the stars of the Big Dipper (or any other group) guide you?  It’s a method called “star hopping.” Star Hopping is the popular technique for jumping from one star or star pattern to another, and is much easier than trying to learn the stars by identifying “constellations” (the mythological figures). For example, with the Big Dipper in its highest position, we can use the curve of its three handle stars to “Arc to Arcturus” and then “Spike to Spica.”

These are the kinds of phrases that help us to remember our star hops. Following the arc of the Big Dipper’s handle outward curves us to a bright orange star in Bootes, the Herdsman. Called Arcturus, it’s the fourth brightest star in the night sky, over 36 light years away. And if you keep the curve going further south, you’ll find Spica, the brightest star in Virgo the Goddess of Harvest, a “blue giant” star over 12,000 times more luminous than our sun.

The Whirlpool Galaxy near the Big Dipper

The Whirlpool Galaxy near the Big Dipper

Star hopping also allows you to pinpoint targets in the sky for binoculars and telescopes. For example, we’ll show you how a simple star hop from Arcturus can get you to M3, a beautifully rich globular cluster holding hundreds of thousands of stars. Or how another hop from Mizar and Alkaid, the two end stars of the handle of the Big Dipper, can point you to the famous Whirlpool Galaxy, another grand island of stars like the Milky Way 23 million light years away.

While Mars is receding from us, it is still the closest it’s been to Earth in over two years. You can find Mars as an organgish star at about 14 degrees west of Spica. Put another way, if you’re facing south, place your fist horizontally at arms length with Spica on the left edge. Mars will be just beyond the right edge of your fist.

Saturn is getting higher in the eastern sky

Saturn is getting higher in the eastern sky

A wonderful sight for telescopes of any size is the planet Saturn, located in Libra (about 25 degrees SE of Spica). Its rings can be seen even in small telescopes with as little as 30 power (30X normal size). Star hops for the planets eventually change because they are the “wanderers,” other worlds orbiting the sun that change their position among the stars over weeks and months and years.

Come and join us this Saturday, June 7 at 6:45 pm in the Hansen Dome Theatre for Gateway to the Stars!  Tickets are only $2 and are free for planetarium members.

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