The sidereal messenger of Galileo Galilei

Accordingly, on January 11th I saw an arrangement of the following kind (Fig. 4), namely, only two stars to the east of Jupiter, the nearer of which was distant from Jupiter thr...

For the sake of being more easily understood, I will suppose a tube A B C D.[7] Let E be the eye of the observer; then, when there are no lenses in the tube rays from the eye to...

I wish in this place to assign the cause of another lunar phenomenon well worthy of notice, and although this phenomenon was observed by me not lately, but many years ago, and h...

Produced by David Edwards, Turgut Dincer and the Online Distributed Proofreading Team at http://www.pgdp.net (This file was produced from images generously made available by The...

[20] Kepler says in his introduction to his _Commentaries upon the Motions of the Planet Mars_, that the theory of gravitation depends on certain axioms, one of which is that “h...

“È tempo che io deciferi a Vostra Signoria Illustrissima e Reverendissima e per lei al Sig. Keplero le lettere trasposte le quali alcune settimane sono le inviai; è tempo dico,...

But the satellite on the east was seen to be further off than before, being at a distance of 11´ from Jupiter. On this night, for the first time, I determined to observe the mot...