5. Stellar parallax
Stellar parallax is one which was NOT observed by Galileo in above list.
It was first measured by Friedrich Bessel in 1838.
Explanation:
- Craters on the Moon: Galileo was probably the first scientist to observe 'Craters on the Moon' in 1609.
- Phases of Venus: The full planetary 'phases of Venus' was first observed by Galileo at the end of 1610 (published in 1613 in letter on Sunspots).
- Sunspots: Galileo and Thomas Harriot observed 'Sunspots' in the end of 1610.
- Jupiter's moons: Jupiter's moon (Io, Europa, Ganymede, and Callisto) were first seen by Galileo Galilei in Dec 1609 or Jan 1610. Later, it was recognized by him as Jupiter's moon in March 1610. They are also known as Galilean moons.
>> But, The first successful measurements of stellar parallax were made by Friedrich Bessel in 1838.