[yarddog]

The optical quality must have been amazing for the time. I have two 20 and 30 power high end spotting scopes, both have ED glass and I have difficulty making out the moons of Jupiter or the rings or Saturn yet Galileo could see them with an uncoated lens.

[SunkenCiv]

He had cleaner skies, and probably somewhat cooler weather, plus he probably viewed when the planets' positions were optimum. :')

• Galileo-Kepler Correspondence, 1597

World's oldest telescope?
by Dr David Whitehouse
Thursday, July 1, 1999

According to Professor Giovanni Pettinato of the University of Rome, a rock crystal lens, currently on show in the British museum, could rewrite the history of science. He believes that it could explain why the ancient Assyrians knew so much about astronomy. It is a theory many scientists might be prepared to accept, but the idea that the rock crystal was part of a telescope is something else. To get from a lens to a telescope, they say, is an enormous leap. Professor Pettinato counters by asking for an explanation of how the ancient Assyrians regarded the planet Saturn as a god surrounded by a ring of serpents?

[the_Watchman]

Back in the 1970’s there was a Scientific American article talking about either an asteroid or a comet. The people who were tracking a modern sighting of this astronomical artifact were trying to extrapolate back in time and concluded that it might have been visible to Galileo during his months of logging the moons of Jupiter.

The rest of the article speculated on Galileo’s equipment and techniques. He had successfully calculated the periodicity of several of Jupiter’s moons using what was probably an 8 power telescope [I could be way off, but 8 is what I remember.] He also plotted the trajectories of the moons as they transited across the surface of the planet.

They presume that he held graph paper up to see with one eye while he sighted Jupiter with his other eye. He moved the paper until the images were superimposed and then counted grids. He apparently did not document his approach, so this was speculation on their part.

Low and behold, in one corner of his charts Galileo noted a bright object moving in the correct direction from night to night which could very well have been the sought after comet or asteroid! Thus the investigators got a data point from nearly 400 years ago.

Like a previous poster pointed out, Galileo had the advantage of a clean atmosphere and nearly no city lights! :)

[plsvn]

the rings or Saturn yet Galileo could see them with an uncoated lens.

Actually Galileo didn't make out the rings of Saturn as rings. He though the planet Saturn had two moons, one on either side.