The Essential Galileo (14 page)

Of the stars east of the planet, the one in the middle was two minutes and twenty seconds from Jupiter, and the star further to the east was thirty seconds from the middle star; the star on the west was ten minutes from Jupiter. They were in the same straight line nearly, except that the star on the east nearest to Jupiter was raised a little towards the north. At the fourth hour, the two stars on the east were even closer together, for they were only twenty seconds apart, thus:

In these two observations, the western star appeared rather small.

On 1 February at the second hour of the night, the arrangement was the following;

The star furthest to the east was six minutes from Jupiter, and the western star eight minutes. On the east side, there was a very small star at a distance of twenty seconds from Jupiter. They made a perfectly straight line.

On 2 February the stars were seen arranged thus:

There was only one on the east, at a distance of six minutes from Jupiter, which was four minutes from the nearest star on the west; and between this star and the one further to the west there was an interval of eight minutes. They were in the same straight line exactly and were nearly of the same magnitude. But at the seventh hour there were four stars, two on each side of Jupiter:

Of these stars, the most easterly was four minutes from the next; this star was one minute forty seconds from Jupiter, which was six minutes from the nearest star on the west; and this one was eight minutes from the star further to the west. And they were all again in the same straight line, drawn along the zodiac.

On 3 February at the seventh hour, the stars were arranged in the following way:

The star on the east was one minute and thirty seconds from Jupiter; the nearest star on the west, two minutes; [88] and there was a long distance, ten minutes, from this star to the star further to the west. They were exactly in the same straight line and of equal magnitude.

On 4 February at the second hour, four stars attended Jupiter, two on the east and two on the west, arranged in one perfectly straight line, as in the following figure:

The star furthest to the east was three minutes from the next; this one was forty seconds from Jupiter, which was four minutes from the nearest star on the west; and this one was six minutes from the star further on the west. In magnitude they were almost equal, but the star nearest to Jupiter was rather smaller in appearance than the rest. Then at the seventh hour, the eastern stars were only thirty seconds apart:

Jupiter was two minutes from the nearest star on the east and four minutes from the next star on the west; and this one was three minutes from the star further to the west. They were all equal in magnitude and arranged in a straight line drawn along the ecliptic.

On 5 February the sky was cloudy.

On 6 February only two stars appeared, with Jupiter between them, as is seen in the following figure:

The star on the east was two minutes from Jupiter, and the one on the west three minutes. They were in the same straight line with Jupiter and equal in magnitude.

On 7 February there were two stars by the side of Jupiter, both of them on the east of the planet, arranged in this manner:

The intervals between the stars and from Jupiter were equal, namely, one minute; and a straight line would go through them and the center of Jupiter.

On 8 February at the first hour, there were three stars, all on the east side of Jupiter, as in this diagram:

The nearest to Jupiter, a rather small one, was one minute and twenty seconds from the planet; the middle one was four minutes from this star and was rather large; the star furthest to the east, a very small one, was twenty seconds from the second star. It was doubtful whether the one nearest to Jupiter [89] was a single star or two starlets, for sometimes it seemed that there was another star next to it further east, extraordinarily small and only ten seconds from it. They were all situated on a straight line drawn along the zodiac. At the third hour, the star nearest to Jupiter was almost touching the planet, for it was only ten seconds from it; but the others had gone further off, for the middle one was six minutes from Jupiter. Finally, at the fourth hour, the star that was previously the nearest to Jupiter joined with the planet and disappeared.