Driftless Dark Skies: Binoculars

April 1st, 2016 by John Heasley

When it comes to stargazing, two eyes are better than one.  If we imagine an astronomer, we probably picture a person looking into a thin tube mounted on a tripod.  My experience is that many telescopes go unused because they are complicated to set up, difficult to use, heavy to move, or disappointing to look through.  Binoculars make stargazing fun and easy. 

Many of us already own binoculars, so there’s no cost.  If you do buy binoculars and lose interest in stargazing, you can use them for birds or wildlife or landscapes.  That’s great news for parents who may not want to add to that collection of things tried and abandoned.  I have learned from public programs than younger children can have trouble using a telescope.  They look at the eyepiece rather than through the eyepiece.  Binoculars are more intuitive for them. 

Binoculars help us to see more.  You want to be able to hold them comfortably, so the largest size I recommend is 7×50 or 10×50.  The first number tells you the magnification (7x or 10x).  The second number is the width of the lens in millimeters (about 2 inches).  More important than making small objects bigger, binoculars make dim objects 10-100x brighter.  On a dark night in the Driftless Area, you might be able to see 1000 stars with your eyes alone.  With binoculars you increase that to 50,000 stars.  Lying on a blanket, air mattress, or reclining chair keeps your view steady. 

Binoculars let us see the colors in the night sky.  At night, we are mostly using the rods in our retinas and the world is monochromatic.  Binoculars gather enough photons to activate the cones in our retinas.  We get to see the red of Betelgeuse, the orange of Arcturus, the yellow of Capella, the green of the Orion Nebula, and the blue of Rigel. 

The Pleiades star cluster consists of 3000 stars at a distance of 400 light years. NASA image.

The Pleiades star cluster consists of 3000 stars at a distance of 400 light years. NASA image.

Many sights are better in binoculars than in a telescope.  The seven sisters of the Pleiades become dozens of stars.  The Andromeda Galaxy is nicely framed by the blackness of space.  The middle “star” of Orion’s sword is revealed as a nebula.  The hazy path of the Milky Way turns out to be stars too many to count.  The Moon is transformed to a world with craters and mountains and valleys.

There’s plenty to enjoy with your binoculars this April.  Look for the crescent moon in the southwest April 8-13.  Scan above the western horizon after sunset April 11-25 for Mercury. Jupiter is near the waxing gibbous moon the evening of April 17.  On the morning of April 25, Mars, Saturn, Antares, and the Moon will be clustered together in the southern sky from midnight to 5am.  Enjoy your double vision! 

John Heasley is an astronomy educator and stargazer who enjoys connecting people with the cosmos. He volunteers with NASA/JPL as a Solar System Ambassador. For more information about stargazing in southwest WI, like Driftless Stargazing LLC on Facebook and find out whenever there’s something awesome happening in the skies. Driftless Dark Skies appears monthly in the Voice of the River Valley.