A transit of Venus: early on the morning of June 8, the silhouette of Venus will slip across the Sun. The event, last seen in 1882, was once the key observation in determining the size of the solar system.

Catching sight of celestial spectacles requires more than patiently sitting at a telescope set up in your backyard. Birdwatchers can pursue their passion almost wherever and whenever they choose. Flower and plant aficionados have only to stroll through their favorite park to enjoy the sights and scents of nature. But to experience the wonders of the heavens, the skywatcher must be in the right place at the right time. Moreover, even predictable astronomical events are often notoriously rare. A total eclipse of the Sun, for example, takes place on average only once every eighteen months. But to see it you may have to travel halfway around the globe to station yourself in ...