Star hopping in the spring sky and an early morning spectacular
Finding your way around the Rochester night sky can be intimidating, especially if you’re new to stargazing. The best way to learn the constellations is to use the ones you recognize to help you find the ones you’re not familiar with or that aren’t as quite as bright. Another fun way to learn to navigate the sky is by star-hopping, traveling from star to star across the celestial dome with your eyes rather than a spaceship. It really works well.
Our starting point is very easy to find — the Big Dipper, the rear end and tail of the constellation Ursa Major, the Big Bear. We won’t worry about the rest of the Big Bear right now; we’ll just concentrate on the Big Dipper. The first thing we want to do is face east. From that vantage point, the Big Dipper will appear to be standing on its handle. Extend the arced line of the handle stars beyond the end of the handle, and you’ll arch yourself directly to the very bright and orange-hued star Arcturus. This famous star-hopping tip is called “arc to Arcturus.”
Arcturus is one of the brightest stars of spring and is the brightest star in the constellation Bootes the Herdsman or Farmer. Facing to the east, Bootes looks much more like a big sideways kite pointing to the left or north, with Arcturus serving as the tail of the kite. Some folks see Bootes as a one-scoop ice cream cone lying on its side.
Astronomically, Arcturus is a bloated red giant star nearing the end of its life. It is 22 million miles in diameter, about 25 times the diameter of our sun. It used to be about the same size as our sun, but crazy helium fusion has caused it to expand rapidly. Arcturus lies about 37 light-years from Earth, with just one light-year equaling nearly six trillion miles. The light we see from Arcturus tonight originally left that great star when Ronald Reagan was still our president in 1985.
Arc to Arcturus isn’t the end of the arc, though. Continue the arc, and you’ll eventually run into a bright star with a slightly blue hue. That’s Spica, in the low southeast heavens. I’ve heard the adage “arc to Arcturus and then spike to Spica.” It’s more like an arc to Spica rather than a spike.
Spica, about 250 light-years away and nearly eight times the diameter of our sun, is the brightest star in the very large but faint constellation Virgo the Virgin. Spica is close to one of my favorite constellations, Corvus the Crow. If you’re still facing east, look for a lopsided trapezoid to the right or south of Spica. That trapezoid is supposed to be a crow? Good luck seeing that.
There you have it, a classic example of star-hopping in the sky. With any star map, you can learn star-hopping tricks to travel all around the great celestial dome, making the stars your old friends.
Early morning planet parade
Getting up really early these next few weeks will be more than worth than while as four bright planets, easily seen with the naked eye, will be very neatly lined diagonally in the low eastern twilight sky. On the right side of the parade will be Saturn and Mars and on the left side will be the really bright planets Venus and Jupiter. All next week Venus and Jupiter will draw closer and closer to each other and on Saturday, April 30, They’ll be less than a half of degree apart. That’s less than the width of your forefinger held at arm’s length. Don’t miss it.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications. Send questions to email@example.com .
The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is rochesterskies.org .