Galileo’s Telescope Helps Kick Off 100 Hours of Astronomy

If you [heart] space, you probably know by now that this Thursday, April 2, marks the start of 100 Hours of Astronomy.

The event will feature live Web casts, sidewalk astronomy, a literal “Sun Day” for solar science, and scads of other public outreach activities around the world.

Kicking off the whole shebang is the opening in Philadelphia of a new exhibit on Galileo, featuring one of the two remaining telescopes built by the man himself about 400 years ago.

The New York Times has a nice preview of the exhibit with video of the telescope (on loan from Italy) arriving at the Franklin Institute.

The ultimate goal of 100 HA is to get people active in astronomy, which can sometimes seem like a very sedentary science. It’s not exactly like a kayak trip down an African river, but there’s plenty of discoveries to be made—you just have to go out and look up.

Of course, the products of astronomy have always been good for capturing public imagination (ahem, Hubble photos), and in addition to Galileo’s rather unassuming brown tube, the Philadelphia exhibit has some definite winners.

One of my favorites is the armillary sphere, a three-dimensional model of how heavenly objects orbit a common center.

Depending on how many spinning rings were involved, armillary spheres could demonstrate all sorts of astronomical activity, from sunrise and sunset at different points on Earth to the motions of the known planets.


A 1585 armillary sphere supposedly used by Johannes Kepler

—Image courtesy Chris Bainbridge

Some scholars put the invention of the armillary sphere all the way back to fourth-century B.C. China, although the Greeks credit one of their own with developing the device in the first century B.C.

Islamic astronomers improved on the Greek design, and their version made it to Europe in the tenth century A.D.

European armillary spheres were popular calculation and teaching tools until around the 17th century, when a humble professor at the University of Padua in Italy published a range of observations that eventually toppled the notion of spherical astronomy.

Although they stand now as representations of one rather large wrong idea, the complex machines have been credited with helping advance early astronomy.

For me, one of the greatest things about these kinds of scientific tools from the Renaissance was a predilection for marrying form to function.

Today no one would expect to see a graphing calculator on display at the MoMA. But in Galileo’s time armillary spheres were often highly decorative objects, and were frequently featured in portraits and paintings as symbols of learning.

Manuel I of Portugal liked the darn thing so much he made it a national symbol, and it survives today as part of the crest on the modern Portuguese flag.


Human Journey