Neptune
I'm not sure the telescope itself had a "name". Neptune was first observed (by someone who recognized it for a planet) at the Berlin Observatory in 1846. Galileo's drawings make it clear that he had seen it over 200 years earlier in 1612 and 1613, but did not recognize it as anything other than just another star.
Saturn was the first planet discovered to have rings. They were first observed by Galileo Galilei in 1610 through his telescope.
Venus
Saturn is the first planet known to have rings. They were first observed by Galileo Galilei in 1610 and later confirmed by Christiaan Huygens in 1655.
Mars has been known for thousands of ears that it is different than the stars and was first observed via telescope by Galileo in 1609.
The first planet to be discovered besides Earth is Mars. It is visible to the naked eye and has been observed for thousands of years by various civilizations.
Uranus was discovered by William Herschel in 1781. It had been observed and recorded before that, but Herschel was the first to realise it is a planet beyond Saturn.
Ganymede is a moon of Jupiter. It is the largest of the four Galilean satellites first observed and noted by Galileo. The other three are Io, Europa, and Callisto.Ganymede is not a planet.
The third planet to be discovered was the dwarf planet Ceres, located in the asteroid belt between Mars and Jupiter. It was first observed in 1801 by Italian astronomer Giuseppe Piazzi.
Ganymede orbits the planet Jupiter. It is the largest of the four Galilean satellites first observed and noted by Galileo. The other three are Io, Europa, and Callisto.
Galileo first observed the planet Mercury through his telescope in 1610.
The first planet discovered using a telescope was Uranus. It was first observed by Sir William Herschel on March 13, 1781.