CAESAREAN

ASTRONOMY

BY PETER APIAN

OF MEISSEN, MOST EXACTLY

COMPOSED, FILLED WITH THE MOST

FAITHFUL INTRODUCTIONS,

DEMONSTRATIONS, AND

EXAMPLES.

FIRST STATEMENT.

The decorative drop cap 'A' marks the beginning of the formal text.
The Solar year.

The diversities of years, which are manifold among various nations, I shall omit for the present, lest I be too long-winded. For some, like the Romans, use the Solar year, of which January is the beginning. For others, like the Arabs, the Lunar year is used, which is observed from September, and so forth. However, I shall set aside all such variations at once, focusing only on the Solar year, which the Sun describes for us by its course. But because this is designated by the unequal motion of the Sun (since the Sun does not reach the same point every year, but adds nearly a quarter part of one day), it causes every fourth year to exceed the three preceding ones by a whole day. This fourth year is therefore called "intercalary," as if you were to say "interposed." Bissextile and intercalary are the same. For the ancients used the term "intercalary" original: "Intercalare" for what we call "to interpose," and in fact one day is interposed which is not in other years; it is also called by another name, "Bissextile" A leap year. The term "Bissextile" comes from the Roman practice of doubling the sixth day before the Kalends of March.. I say, I shall follow this Roman solar year in the present works, according to which I will teach how to find all celestial motions. I shall begin the same from January, which is the end of any preceding year. I wish you to understand it thus: that the beginning is made from the noon of the last day of December. For astronomers perpetually enter their calculations from noon to noon, so that the time before noon is always counted toward the preceding day.

Since, however, I investigate the celestial motions from the year of the world to the beginning of the following year, and I set the "root" root: also called a 'radix' or 'epoch,' it is the reference point in time from which an astronomer calculates the positions of stars or planets at that same year, namely that of Christ, it must not be thought that I am pointing to the twenty-fifth day of December, even though our Savior When Christ was born. was born then, but rather to the end of that same year. For the ancient astronomers cast aside those six days which follow from the 25th to the end of December, and instead referred the "root" to the last day of the same year in which Christ was brought forth into the world, and established it there. But the end of that year is the beginning of the following one. For one who wishes to inquire into the "root" at the day of the Lord’s nativity, it will be necessary to search backward by a space of so many days, as is said. Method of operation. Here I cannot remain silent: up to now almost all astronomers have been deceived by a truly abominable error while they attempted to grasp the courses of the stars, Conjunctions, Oppositions, and other Aspects through the "Root of Christ." They did not notice that they were placing Common and Bissextile years in an equal ratio when they judged the years before and after Christ by a similar proportion, even though the birth of our Savior occurred not Civil year. in a Common or Civil year, but in an intercalary leap year. But I say this to remind those who will one day use their instruments and tables, so that they may act more cautiously and attempt their work more providently. In the present work, this will cause no doubt. Why astronomers are mistaken in computing motions before Christ.

To this, since I see that the older astronomers founded their "roots" with a certain reverence variously upon the beginnings and deaths of kings and leaders—such as at the death of Philip, and at the beginning of the reign of Nebuchadnezzar—I likewise remember some memorable acts, such as that universal flood, etc. Furthermore, I have included some distinguished in learning and the name of Astronomers, so that if there were any who required the celestial courses for their times, they might have them ready at hand. For example: if someone desires to know what locations the stars held in the time of Ovid, let him look in the following table for when Ovid lived. He will find that he died in the 19th year after the Savior; therefore, the motions of the stars must be sought for that number of years. Another example: You hear that a great conjunction preceded the Flood by nearly two years, and you are uncertain whether this is so. The time of CHARLES, Emperor of the Romans, & FERDINAND, King of Rome, Bohemia, & Hungary. You write down the years of the flood that were 3102 before the coming of the Savior, you add 2, and you have 3104. If you now examine that year through an instrument, as shown below, it will immediately become clear whether a great conjunction occurred in the year 3104 or not. Yet another: It is said that there was an eclipse of the Moon in the second year after the birth of the most august CAESAR CHARLES the Fifth,

or in the year immediately before FERDINAND, the most powerful King of the Romans, Hungary, and Bohemia, etc., was born; but you doubt whether this is the case. You shall look in the table of times for the name of King FERDINAND; for next to it, the year 1503 after Christ is offered. Seeing then whether an eclipse of the Moon was seen in the former year—that is, the second after 1500—it will be found to have occurred on October 15, at the third part of one hour after noon. You shall operate in the same way in similar cases.

THE TABLE OF TIMES FOLLOWS.

CHRONOLOGY PRECEDING CHRIST.

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A small portrait of Jesus Christ with a halo.

† JESUS CHRIST THE SON OF GOD IS BORN IN BETHLEHEM of Judea, in which year the salvation of Christians began.

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CHRONOLOGY FOLLOWING CHRIST.

B