Kepler's Complete Works, Vol. I (Opera Omnia)

Astronomical Report

...turned, then under the female rule Referring to the regency of Mary of Guise and the subsequent reign of Mary, Queen of Scots, a harmful discord arose among the appointed provincial councilors, and the hatred of the remaining Spanish troops and the Reformed religion gained the upper hand against all prohibitions and severity. Although it had not yet ripened into a general uprising at that time, the land nonetheless became full of factions and rebellious heads.

In Livonia A historical region encompassing parts of modern-day Estonia and Latvia, the Muscovite Tsar Ivan IV, known as "the Terrible" raged terribly, for which reason this land was forced to secede from the Empire and surrender itself to the protection of the Kingdom of Poland.

In Asia, the two sons of the now old and frail Turkish Emperor Suleiman—Selim and Bayezid—took up arms even further, between whom the Turkish Empire was divided, until Selim overcame his brother in a field battle, drove him into Persia, and had him put to death there.

In the year 1567, on the 9th of April, the sun was covered by the moon at high noon in Rome in such a way that a bright circle still reached out around the moon.

In Leuven, Gemma Cornelius Gemma, a physician and astronomer found the midpoint at 11:40. In Duisburg, Mercator Gerardus Mercator, the famous cartographer found it at 11:43; in Vienna, Austria, Tilemannus Stella at 12:27. In Leuven, nearly 9 inches digits: a measurement of eclipse magnitude where 12 units equal the full diameter of the sun were covered; in Tübingen, nearly 10.

My calculation from Tycho Brahe shows at Rome (which has the same meridian as Uraniborg Tycho Brahe’s observatory on the island of Hven) only 6 minutes before 12 o'clock. And if the observation by Clavius Christopher Clavius, the Jesuit mathematician who led the Gregorian calendar reform truly occurred in Rome, then my calculation gives a visible latitude original: "latitudinem visam" of 1° 30' North, and the moon should have appeared wider than the sun. Thus, only a very narrow horn, not even one minute wide, would have remained visible at the bottom part, and it would not have reached even to the middle of the sun, while at the top nothing of the sun should have remained visible. But when I use the physical equation of time a correction applied to solar time to account for the Earth's elliptical orbit, I get the midpoint for Rome and Uraniborg at 20 minutes after 12 o'clock, which is closer to all observations. On the other hand, for Rome, nearly 2 minutes remain for me at the bottom, so that the shadow must have passed over Milan and Venice; this agrees better with the 10 digits observed in Tübingen.

Yet it is to be suspected that a thick, flaming matter must have been around the sun, which also extended beyond the moon, as in the years 1605 and 1598. For the moon was nearly as wide this time as in the previous eclipse, and the sun likewise. If the moon could completely cover the sun then, surely the sun alone could not have poked out all around now; rather, such a matter, as mentioned, must have done it, of which we indeed have many indications in lunar eclipses and elsewhere. Or it could also be that a transparent air clothes the moon, in which the sunshine refracts—as happens with us and in our atmosphere—sometimes more than others.

And because both lights were in the 29th degree of Aries near the Dragon’s Tail The descending node of the moon's orbit, a point where eclipses can occur, it follows that the moon’s shadow came over Spain and the Mediterranean Sea, passed through Italy lengthwise, and moved through the Adriatic Sea into Turkey and the Orient.