Galileo Galileo (February 15, 1564 - January 8, 1642)
One of the first who used a telescope (a term he coined in April, 1611) to
observe the skies in late 1609, and the first to publish his observation to a
wider audience; a summary of the first discoveries was published in his famous
Sidereus Nuncius (Siderial Messenger) in May 1610. His first telescope
had a free aperture of 16 mm and magnification of 21.
Discovered many phenomena:
Note: Some of these discoveries were independent rediscoveries, e.g. Thomas
Harriot discovered the mountains on the
and sunspots earlier.
- November 30 to December 10, observations of the
Discovers "mountains" (and craters).
- November XX, 1609, Milky Way consists of
- 1609, numerous faint stars, e.g. in Orion's Sword (but failed to perceive
the Orion Nebula) and in the
- 1609, Praesepe, M44, is a star cluster.
- January 7, 1610, 3 moons of Jupiter; January 15, 4th moon.
See Galileo's discovery of Jupiter's moons.
- July 1610, strange appearance of
(suggestions caused by the Rings)
- December 1610, phases of Venus.
- May 1611,
Galileo's sunspot drawings.
- February 1617, three stars of the
Trapezium cluster in M42 (without noting
the Orion Nebula).
- Pre-discovery sighting of Neptune in 1612.
Previously, Galileo had observed and studied the "New Star" of 1604
Posthumous honors are numerous and include the naming of asteroid (697) Galilea,
(discovered February 14, 1910 by J. Helffrich in Heidelberg, provisionally named
1910 JO and, from independent sightings, A910 DA, 1945 GE, and 1979 FL2), Moon
Crater Galilaei (10.5N, 62.7W, 15.0 km diameter, named 1935), Mars Crater
Galilaei (5.7N, 27.0W, 137.3 km, named 1973) and "Galileo Regio" on Jupiter's
"Galilean" Moon Ganymede,
the naming of the Galileo Jupiter Orbiter spacecraft,
as well as trivial things like street names,
e.g. in Paris, France: Rue Galilée,
and in Munich, Germany: Galileiplatz.
- Kenneth Glyn Jones, 1968.
The Search for the Nebulae -- II.
Journal of the British Astronomical Association, Vol. 78, No. 5 (1968),
p. 360-368. Section on Galileo: p. 362-363.
Reprinted in: The Search for the Nebulae. Chalfont St. Giles, 1975.
- Kenneth Glyn Jones, 1991.
Messier's Nebulae and Star Clusters. 2nd ed, Cambridge University Press,
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