Galileo’s Telescope
Galileo was told about new “looker”
- Promptly (1609) built his own
- modest, 1 inch aperture
- comparable to 12x binoculars today
- not the equipment, but the brain behind it
- Pointed into night sky -- amazing! (The Sidereal Messenger)
- Sun had spots model
- Sun not perfect sphere
- and they moved!
- suggestion that spots caused by orbiting body disproved by Galileo
- Rotation period of sun ~ 25 days
- Structure on the Moon
- mountains and valleys
- Moon not perfect sphere either
- used length of shadows to estimate height of mountains