Astronomers have been observing the comet for more than 75 years.

Ancient astronomers observed points of light that appeared to move among the stars.

Hence the astronomer observes, that the position of the star changes.

The astronomers observed Titan on 82 nights in recent months.

This was the first time that astronomers have ever observed a supernova as it occurred.

Still, astronomers cannot observe the objects themselves, only their effects on nearby stars, gas and dust.

Chinese and Japanese astronomers observe what has since come to be understood as a supernova.

By 635 Chinese astronomers had observed that the tails of comets always point away from the sun.

In order to get a better understanding of the mechanism behind jet formation, astronomers have observed their structures.

In the 18th century, astronomers with weak telescopes first observed the phenomenon of stellar death.