Observations of what celestial bodies formed the basis of the first definitions of the speed of light?

In 1676, the Danish astronomer O. Römer first determined the speed of light from observations of eclipses of Jupiter’s moon Io. The position of the satellites is “delayed” by 16.7 minutes, when the observer, together with the Earth, moves to the opposite side of the orbit from Jupiter.
The phenomenon of stellar aberration caused by the Earth’s orbiting the Sun was also used in 1727 by the English astronomer Bradley to determine the speed of light.

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