The Essential Galileo (16 page)

That is, the star on the east was seven minutes from Jupiter, which was five minutes from the next star on the west, and this was three minutes from the remaining star still further to the west. They were all approximately of the same magnitude, rather bright, and in the same straight line, corresponding accurately to the direction of the zodiac.

On 17 February at the first hour, two stars were in view, one on the east, three minutes from Jupiter; the other on the west, ten minutes distant:

The latter was somewhat smaller than the star on the east. But at the sixth hour, the eastern star was nearer to Jupiter, being at a distance of fifty seconds, and the western star was further off, namely twelve minutes. At both observations, they were in the same straight line with Jupiter, and were both rather small, especially the eastern star in the second observation.

On 18 February at the first hour, three stars were in view, of which two were on the west and one on the east:

The distance of the eastern star from Jupiter was three minutes, and of the nearest star on the west two minutes; the remaining star, still further to the west, was eight minutes from the middle star. They were all in the same straight line exactly, and of about the same magnitude. Then at the second hour, the stars nearest to the planet were at equal distances from Jupiter, for the western star was now also three minutes from the planet. At the sixth hour, the fourth star was visible between the star on the east and Jupiter, in the following configuration:

The star furthest to the east was three minutes from the next; this one was one minute and fifty seconds from Jupiter, which was three minutes from the next star on the west; and the latter was seven minutes from the star still further to the west. They were about equal in magnitude, except that the star on the east nearest to Jupiter was a little smaller than the rest. And they were all in the same straight line parallel to the ecliptic.

[92] On 19 February at forty minutes, only two stars were in view, west of Jupiter, rather large, and arranged in the same straight line with Jupiter, in the direction of the ecliptic:

The nearer star was seven minutes from Jupiter and six minutes from the star further to the west.

On 20 February the sky was cloudy.

On 21 February at one hour and thirty minutes, three stars, rather small, were in view, placed thus:

The star to the east was two minutes from Jupiter, which was three minutes from the next on the west; and this one was seven minutes from the star further on the west. They were exactly in the same straight line parallel to the ecliptic.

On 25 February at one hour and thirty minutes (for on the three previous nights the sky was overcast), three stars appeared:

Two were on the east, four minutes apart, the same as the distance of the nearer star from Jupiter; on the west there was one star at a distance of two minutes from Jupiter. They were exactly in the same straight line in the direction of the ecliptic.

On 26 February at thirty minutes, only a pair of stars was present:

One was on the east, ten minutes from Jupiter; the other was on the west, at a distance of six minutes. The eastern star was slightly smaller than the western. But at the fifth hour, three stars were visible:

On 27 February at one hour and four minutes, the stars appeared in the following configuration:

Besides the two already mentioned, a third star was in view, on the west, near Jupiter, very small; it had previously been hidden behind Jupiter, and it was now one minute from the planet. The star on the east was seen to be further off than before, being at a distance of eleven minutes from Jupiter. On this night, for the first time, I decided to observe the progression of Jupiter and its adjacent planets along the zodiac, by reference to some fixed star; for there was a fixed star in view, [93] eastwards of Jupiter, at a distance of eleven minutes from the eastern planet, and a little to the south, in the following manner: