Caption: Moon maps drawn by Galileo (1564--1642) in 1609 using the telescope for observations of the Moon. They were published in Sidereus Nuncius (1610, in English The Star Messenger).

Features:

1. Galileo's moon maps are NOT perfect. The early telescopes had many imperfections compared to even cheap modern telescopes and Galileo was observing and sketching at the same time---a tricky business.

2. However, Galileo did do a good job of identifying lunar features in general.

   Importantly, lunar mountain shadows, seen most clearly at the terminator (the line dividing the day and night sides of the Moon), verified varying elevation occurred on the Moon NOT just varying color.

   Clearly, the Moon was a body NOT altogether unlike the Earth. It was NOT a perfect sphere as in Aristotelian cosmology.

   And if the Moon was Earth-like, then the Earth was Moon-like. The argument that the Earth could NOT be planet because it was unlike the celestial bodies vanished.

   Note Galileo's training in and interest in painting and chairoscuro made him sensitive to shadow effects (see Wikipedia: Galileo: Moon).

3. Galileo also got the locations of the lunar maria more or less right. For that reason, the Leaping Moon Rabbit is clearly seen---head on the east, long ears extending over the north, hindquarters and tail on the west.

   Note that Galileo and other earlier observers first thought the maria (singular mare) were seas and oceans, and so gave them the name maria which is just Latin for seas. Galileo himself realized this could NOT be right fairly soon???. But it is right in a sense---the maria are solidified plains of lava: i.e., lava plains.

4. Galileo was NOT accurate in all details. For obvious example, what is that giant lunar crater in the middle south? It's probably Galileo's exaggerated interpretation of Crater Tycho, but it's too large a crater compared to Crater Tycho, NOT quite in the right place, and has NO crater rays.

   It may be that Galileo in his pioneering moon maps was trying to give the right impression of what the Moon's cratered surface was like in general rather than making an effort at precise rendering. So Galileo probably intended the false giant lunar crater to be representative of lunar craters in general.

5. By the by, Galileo did NOT invent the telescope (see Wikipedia: History of the Telescope: The first known telescopes). It was invented in 1608 in the Netherlands. There are rival claimants for being the original inventor.

   A bit of history:

   1. After learning of the invention of the telescope in 1609, Galileo put his great experimental skill to work and built the best available early telescopes. He did NOT work out any theory of the telescope from geometrical optics---which seems odd since he was adept at geometry. Perhaps, being hot on the trail, he did NOT have the patience for that. He improved the telescope by empirical means: trial, error, adjustment. This is common practice in technology since ever it was.

   2. Galileo then showed great energy in using the telescope to make many of the first or nearly first great telescopic discoveries.

      He liked to claim that he was absolutely first in all of them. This is NOT true. There were other rival discoverers playing around with early telescopes and the absolutely first discoverers of things are sometimes arguable. Galileo was certainly NOT aware of his rivals, at least originally.

      For example of an unknown rival (who stayed unknown to Galileo), Thomas Harriot (c.1560--1621) drew Moon maps (see The Galileo Project: Thomas Harriot's Moon Drawings) starting from 1609 Jul26 (see Wikipedia: Thomas Harriot: Later years) some months before Galileo. But Harriot did NOT publish his results. NOT publishing his results was a common problem with Harriot. He would rank with Galileo and Johannes Kepler (1571--1630)---though a bit below---as one of leaders of the Scientific Revolution (c.1543--c.1687) if he'd ever published his important discoveries and innovations. But he did NOT, and so he is just an interesting specimen in the history of science.

   3. What set Galileo apart from his rivals in the early telescopic work was his energy in making observations in 1609 and then publishing the discoveries, etc., quickly in the Sidereus Nuncius (1610, in English The Star Messenger), which is a short Latin book intended for the general public, NOT just astronomers

   4. Galileo intended his title to mean "message from the stars", but it could also be translated as "messenger from the stars", and this translation was almost immediately adopted by the public. Galileo---who was more than a bit vainglorious---acceded to this change in meaning---he was the starry messenger---the Sidereus Nuncius.

   5. The Sidereus Nuncius made Galileo famous throughout Europe---which he wasn't before.

   6. The Sidereus Nuncius refutes Aristotelian cosmology and presents strong evidence for the heliocentric solar system model. However, many contemporaries did NOT acknowledge the former and the latter was by implication. Galileo only hints at his own Copernicanism. Kepler from his ealiest published work in 1596 was openly a Copernican.