More accurately, he was the first to publish. There were other people with telescopes at the time and some also looked at celestial objects. For example, a guy named Simon Marius discovered the Galilean satellites at pretty much the same time as Galileo, but Galileo gets all the credit. Marius’ names for them ended up being accepted, though.
I’ve heard said that Galileo’s view of Jupiter and its moons wasn’t any better than what your binocular gives you, and was possibly worse. It does take a steady hand to get a good view. When my daughter was in middle school we used my telescope to watch Jupiter’s moons for a few weeks to see if she could predict which dot was which, and try to predict the next day’s positions (it was a science fair project). It was hard to do figure it which moon was which, so Galileo must have lots of fun.
Another thing you should try when camping is to find the Andromeda galaxy, easiest in the summer. After finding it with binoculars, try to see if you can see it without aid. Seeing another galaxy with your naked eyes, and recognizing it as a galaxy that you can see is mind-blowing.
That, and his optics were much lower quality than what any modern device would use. Not bad for someone hand-grinding lenses and making up his own techniques as he went along, but technology has improved since his time.
Really good ones, maybe, but in your standard 10x50 binoculars it looks oblong. You need about 30x to really see the rings. Galileo’s telescope was about 20x.
I’ve been told that he first thought it was a planet with ears.
I’ve looked through a supposedly accurate reproduction of Galileo’s telescope. It was terrible. Very fuzzy, very narrow FOV. Hard to make out anything. (I only used it during the day, not at night.)
Some years ago when I was living in Carson City at 5,000 feet with dark skies, one August night after studying a Messier chart I walked out with my 7x50s and star-hopped from Andromeda (the constellation) to M-31. Once I had done that it was a snap to repeat the process with my pair of Mk I eyeballs and I had the same sense of wonder. I am seeing the most distant naked eye object there is.
The thing Kepler came up with, with elliptical orbits and equal area orbital speed - was because while everyone agreed - eventually - that Copernicus had explained and simplified a lot, there were substantial numbers of “cosmos deniers” who pointed out “if the planets are moving in circles around the sun at constant speed, and so are we, they are not quite where we should be seeing them in the heavens”. Kepler determined that was because they neither moved in exact circles, nor at constant speed. Then Newton showed that gravitational forces could explain the motion Kepler came up with. It was always a work in progress.
I like that the common Person on the Street would give this as the correct answer despite the more correct answer being ‘The planets Objects in the Solar system are moving in circles orbits around their barycenter with the Sun’.
But at that point we’re in Asimov’s The Relativity of Wrong* land.
*Geocentrism is making a comeback thanks to Flat Earthers and other stupid folks.
I hate to squelch anyone’s sense of wonder, but we are nitpickers here on the SDMB.
I believe the furthest naked-eye object is M-33, the Triangulum Galaxy. It’s not very bright (apparent magnitude 5.72) because it’s smaller, but it is somewhat further than Andromeda (2.73 vs 2.5 million lightyears). You’d need a dark site to see it, but it sounds like that’s what you had in Carson City.
There was an admission they had no info on stars… But a very good explanation for the wanderers would explain (eg allow measuring the distance to them. ) stars too, and explain the galactic galaxy (I mean, the milky galaxy … the galactic way … “the milky way” galaxy means milky, you know ? all galaxies are therefore milky … but ok “the milky way” is our galaxy ) they hadn’t neglected that they wanted an explanation for stars. just they had no info so far. But Ok, they accepted the wanderers could be separate to stars and the milky way.
That is not the real pic, though; here is the one from @MikeS 's link:
An ellipse is basically a circle + an epicycle, though, so the Copernican picture does not make the epicycles go away—the planets are seen not to be moving in circles at constant speed.
Some people (i.e., Tycho Brahe) were able to make observations good enough to compute the planetary orbits (i.e., where we should be seeing them in the heavens) more accurately. I recall there was even a discussion on this board concerning Kepler’s geometric procedure for calculating the orbit of Mars (eccentricity 0.093)
And note that Brahe made up his own system, which was a compromise of Ptolemy and Copernicus. That is, the Sun and Moon went around the Earth and all the planets went around the Sun. It still had circular orbits, although he didn’t actually work out the math on his system, so it had no epicycles or deferents.
Tycho Brahe demonstrated that comets were at least as far away as the moon in 1577, by combining his observations with those of others and proving that comets showed no parallax. All Halley added was the demonstration that comets could be periodic as well.