It's time to pay pilgrimage to the first telescope ever pointed at the sky, and its housed in the Museo Galileo of Florence, along with three floors of strange scientific instruments.
We enter the building and are greeted by a number of elaborate clocks. In fact, everything on display was elaborately decorated, sometimes with the Zodiac, sometimes with a family crest, an homage to the idea that science is also a delicate art. A spec of dust, a shaky hand, is all you need to ruin a measurement and arrive at the wrong conclusion.
Turn the corner to see a massive armillary sphere! An armillary sphere is a device that can recreate the apparent motion of the stars and the planets. Throughout Italy, we've seen these come in two flavors: sometimes the Sun is in the center, and sometimes, the Earth! The earliest known spheres date to Chinese astronomers in the 4th Century BC who used them to measure the positions of the stars.
At 11:30 am, we met with Karen Giacobassi, a didactic at Museo Galileo. She led us through a hidden door to her office (Italy has half a million hidden doors), where we shared ideas about sidewalk astronomy. We found out that Museo Galileo has brought telescopes out in the past, and we hope we left her encouraged to start it up again.
They found that it wasn't easy to schedule a bus to the darker hillside, watch the weather, cancel the bus, cancel the event, etc. Something the Moon Men have learned is that even in a light polluted city, the Solar System's most wonderful sights are still visible. I think Karen felt good knowing that the telescopes could get some use even if they were right outside the museum.
Then Karen showed us a special treat. Recently, they built a working replica of Galileo's telescope. We were fascinated by just how bad it was! The magnification is low, around that of a pair of binoculars. The field of view is small, because Galileo's design used a negative focal length eyepiece, and the image is dim because the lenses are small. At 20X magnification, this telescope wouldn't even be able to view the whole moon in one shot.
In 1610, this was state of the art. With the dark skies of the 17th century, and some patience, Galileo sketched maps of the moon's craters, disproving Aristotle's claim that the moon was a perfect sphere, used the technique of similar triangles (a technique that 10-year-olds now learn in math class) to estimate the height of the mountains, discovered Jupiter's largest four moons, studied the phase of Venus, and even had some theories about sunspots.
Just about everything in the Solar System that you can see through a telescope, Galileo saw it and studied it. Telescope technology exploded and within just 100 years, scientists were building telescopes that you could climb inside!
What an incredible impression you get of the ancient scientific methods when you visit a museum like this!
Later in the day, we visited Galileo's final resting place, and reflected on his mission to share the telescope's discoveries with everyone around him. Karen reminded us, he wasn't always successful. Plenty said that the Medicean moons were a trick of the eye, or some kind of optical illusion. Some wouldn't look through the telescope at all, the idea being altogether offensive. Just like the Moon Men, Galileo struggled to get people to look for themselves.