Some observations, lately made at London, of the planet Jupiter: as also of Saturn.

Abstract

These, as they were made, so they were imparted, by Mr. Hook, as follows: A. 1666, June 26. between 3. and 4. of the clock in the morning, I observed the body of Jupiter through a 60 foot-glass, and found the apparent diameter of it through the tube, to be somewhat more than 2. degrees, that is, about four times as big, as the diameter of the moon appears to the naked eye.