Advertise here with Carbon Ads

This site is made possible by member support. โค๏ธ

Big thanks to Arcustech for hosting the site and offering amazing tech support.

When you buy through links on kottke.org, I may earn an affiliate commission. Thanks for supporting the site!

kottke.org. home of fine hypertext products since 1998.

๐Ÿ”  ๐Ÿ’€  ๐Ÿ“ธ  ๐Ÿ˜ญ  ๐Ÿ•ณ๏ธ  ๐Ÿค   ๐ŸŽฌ  ๐Ÿฅ”

kottke.org posts about Sidereus Nuncius

How well did Galileo observe Jupiter’s moons?

In the pages of Sidereus Nuncius, Galileo described the four large moons of Jupiter in a series of 64 sketches which looked a lot like ASCII art in the text:

Sidereus Nuncius

Using an online tool for computing the positions of Jupiter’s moons, Ernie Wright compared Galileo’s sketches to the moons’ actual motions.

Galileo moons

Click through for an animated GIF of all the comparisons. Not bad for the telescopic state of the art in 1610. For a taste of how celestial objects actually appeared when viewed through Galileo’s telescope, check out this video starting around 7:30. (thx, john)