Have you ever wanted to be Galileo for a day? If you own a pair of binoculars (or a small backyard telescope), now is the time to channel your inner Galileo! Galileo’s 17th century telescopes were very small by today’s standards, with a similar magnification to a pair of common binoculars today. So why not dust off those birdwatching binocs and turn them skyward over the next few weeks?
Our first stop is the planet Venus, now hard to miss in the western sky after sunset. Galileo noticed that Venus shows phases like the moon. The phases won’t be as obvious as shown in the above diagram, so you need to be patient, and hold your binoculars very steady. Use a camera tripod, or try steadying your arms by resting your elbows on a hard surface like a picnic table. Another trick is to hold the binoculars near the far end, where the light enters, rather than putting your hands close to your eyes. This will hold them steadier, because most of the binoculars’ weight is on the far end where the main lenses are.
Our second stop is more towards the south, a “star” that is a little dimmer than Venus, but still rather obvious to the unaided eye. This is Jupiter. Galileo discovered four moons orbiting Jupiter (as shown in a page of his observations reproduced above), which we now collectively call the Galilean moons in his honor. Again, holding the binoculars steady is key here. Watch the moons appear to move relative Jupiter from night to night!
Finally, if the moon is out, don’t forget to train your binoculars in its direction. Galileo studied the craters on the moon, and so can you!
Put on Bohemian Rhapsody, grab your binoculars, and before long you’ll be singing “Galileo, Galileo” as you reproduce the groundbreaking observations of more than 400 years ago. It’s an experience not to be missed!