The "Calendar of Numa" and the Pre-Julian Calendar

1949 ◽  
Vol 80 ◽  
pp. 320 ◽  
Author(s):  
Agnes Kirsopp Michels
Keyword(s):  
Julian Calendar

Hesitant Steps: Acceptance of the Gregorian Calendar in Eighteenth-Century Geneva

2006 ◽  
Vol 75 (3) ◽  
pp. 544-564 ◽  
Author(s):  
Jennifer Powell McNutt
Keyword(s):  
Eighteenth Century ◽  
Religious Identity ◽  
Catholic Church ◽  
Julius Caesar ◽  
Ancien Regime ◽  
Gregorian Calendar ◽  
Julian Calendar ◽  
Ancien Régime ◽  
At Will ◽  
The Catholic Church

History demonstrates that the calendar is a tool of far more significance than simply a means to organize units of time. For Roman high priests prior to the reign of Julius Caesar, the calendar was a tool of power, symbolizing political supremacy over society through the manipulation of time at will. Under Pope Gregory XIII, the calendar was a symbol of papal responsibility to ensure the proper worship of the Catholic Church. In the case of European Protestants, the Julian calendar was a symbol of religious identity and protest against Catholic domination. Likewise, within revolutionary France, the Calendrier Républicain symbolized the rejection of the Ancien Régime and Catholicism. These few examples are an indication that throughout history in various times and places calendars have proven to represent more to humanity than mere time reckoning methods. Consequently, one may approach the study of the calendar as a means to grasp cultural and religious identity within specific regional contexts.

scholarly journals An Overlooked Construction Manual for the Quadrans Vetustissimus

Nuncius ◽  
2019 ◽  
Vol 34 (3) ◽  
pp. 517-534 ◽  
Author(s):  
C. Philipp E. Nothaft
Keyword(s):  
Graphical Method ◽  
Sine Function ◽  
Julian Calendar ◽  
Solar Declination

Abstract This article presents an edition and brief analysis of the previously overlooked text De compositione quadrae, which is transmitted as part of a scientific miscellany assembled at Worcester Cathedral Priory no later than 1140. De compositione quadrae offers hitherto unavailable information on the construction of the so-called quadrans vetustissimus, a version of the universal horary quadrant circulating in Latin Europe during the eleventh and twelfth centuries. It is particularly noteworthy for its description of a graphical method of inscribing the months of the Julian calendar on the quadrant’s cursor, which successfully approximates the sine function that determines the change of solar declination in the course of a year.

scholarly journals 30. Fireball radiants of the 1st–15th centuries

1968 ◽  
Vol 33 ◽  
pp. 308-318 ◽  
Author(s):  
I.S. Astapović ◽  
A. K. Terenteva
Keyword(s):  
Middle Ages ◽  
Ecliptic Plane ◽  
Meteor Shower ◽  
The South ◽  
13Th Century ◽  
Large Area ◽  
Process Data ◽  
Retrograde Motion ◽  
Julian Calendar ◽  
The North

The works of E. Biot, published by the Institut National de France in 1848, made it possible to study material recorded in volumes 191 and 192 of the well-known 13th-century Encyclopaedia of Ma Touan-lin as well as records from other sources. They contain observational data of 24 centuries (especially from the 11th century) on more than 1500 fireballs, with descriptions of their positions with respect to the stars as well as descriptions of their physical, kinematic and other properties. The observation dates of the lunar calendar have been converted by Biot into dates of the Julian Calendar.We have been able to process data on 1220 fireballs. As a result of this radiants were obtained for 153 meteor showers, seven of which belong to great showers. Out of the remaining 146 radiants of the minor showers, 80 radiants are more certain than the remainder.The radiants were deduced from observations on dates recorded in short intervals from several years to several decades. First the dates of visibility were obtained along with the activity and radiants of great showers which are still active. In the Leonid shower, with retrograde motion, a shift of visibility dates to a much later period has been noted corresponding to a forward motion of the orbit's node, whereas a retrograde motion of the node is observed in the Quadrantids (i < 90°). In the Lyrids and Perseids, whose orbits are nearly perpendicular to the ecliptic plane, the nodes experienced no perturbations, and the visibility epochs for the showers remained the same during a period of 1000 years and longer. The motion of apsides resulted in a shift of the radiant; the increase of the ecliptical latitude indicated secular augmentation of the orbit's inclination (Geminids, η-Aquarids, Orionids, Leonids). The radiant of the Perseids was located in Cassiopeia, where the radiant of the present-day Cassiopeids is to be found. It appears that the Perseid stream began to cross the orbit of the Earth in 830 A.D.In the δ-Aquarids the North branch was active, while there is no evidence that the South branch had existed earlier than 900 years ago. The Virginids, Librids, Scorpionids, Sagittarids and Aurigids were quite appreciable and their studies furnish much interesting data. Particularly active were the Taurids; their North and South branches were observed over 1000 years back. The South Taurids were about half as active as the North Taurids (at present this relation is reversed). Very active were the Cygnids (July–August), which presented at that time a compact shower, now disrupted into a series of minor showers with radiants spread over a large area of the celestial sphere. Of definitive interest is the radiant of the great meteor shower observed in 1037 (August 21 by the Julian Calendar, September 9 by the Gregorian Calendar, 1950–0), α = 324°, δ = + 1°(1950–0).Some of the showers active in these early centuries are now unknown; on the other hand, some showers which are well known now were not observed in the Middle Ages. In the past millennium only those streams have survived whose orbits were so situated with respect to the orbits of the outer planets, that they were not subjected to any considerable perturbations produced by these planets.

scholarly journals The Birthday of Augustus and the Julian Calendar

1912 ◽  
Vol 6 (2) ◽  
pp. 73-81 ◽  
Author(s):  
T. Rice Holmes
Keyword(s):  
The Sun ◽  
Julian Calendar ◽  
Recent Edition

Suetonius says that Augustus was born on the ninth day before the Kalends of October (a. d. VIIII. Kal. Oct.), in the year when Cicero and Antonius were consuls (691 [63 B.C.]), a little before sunrise,1 and also that he was born under Capricorn.2 Mr. H. W. Garrod, in his recent edition of Manilius,3 maintains that the date which Suetonius gives belonged to the pre- Julian calendar, and corresponded with December 20 of the Julian. Remarking that, ‘ according to our present reckonings,’ the sun enters Capricorn on December 22, he adds that ‘the astronomers of Cicero's time placed the beginnings of the sign some 7 degrees in advance of our reckonings. If, therefore,’ he concludes, ‘ Augustus was born on Sept. 22 paulo ante solis exortum, Capricorn was his natal sign.’

Clavius

1931 ◽  
Vol 24 (1) ◽  
pp. 40
Keyword(s):  
Julius Caesar ◽  
Gregorian Calendar ◽  
Julian Calendar ◽  
German Scholar ◽  
Mathematical Activities

Christopher Clavius (1537-1612) was a German scholar who became a Jesuit and who spent the latter part of his life in Rome. His portrait gives evidence of his varied mathematical activities for the instruments hung on his wall or standing on his desk indicate his interest in astronomy and trigonometry, the drawings under his hand and the compasses be holds show his work in geometry, and the books piled before him may be looked upon as being his arithmetic, his algebra, and his commentaries on the works of earlier writers. Clavius was influential through his power as a teacher and through the popularity of his publications rather than for his discoveries in the field of mathematics. What is perhaps his greatest achievement was in connection with the adoption of our present calendar. Here, again, his role was to interpret and execute the ideas of others. It is unnecessary to discuss the details of the omission of ten days from the year 1582 in order to bring the calendar year into harmony with the astronomical year or the replacing of the Julian calendar sponsored by Julius Caesar by the Gregorian calendar of Pope Gregory XIII, but it is interesting to note that Clavius was summoned to Rome to explain the theory of the innovations. Ball notes* that Clavius rejected the proposal of omitting a leap year day once in 134 years and substituted the omission of three days in a 400 year period.

Astrology for Maecenas

Antichthon ◽  
1982 ◽  
Vol 16 ◽  
pp. 88-96
Author(s):  
D.A. Kidd
Keyword(s):  
Special Interest ◽  
The Sun ◽  
Julian Calendar ◽  
Time Of Year ◽  
A Minor ◽  
Limited Scope

Astronomical themes, with a rather limited scope, were a minor but recurrent element in ancient poetry, and Horace makes considerable use of them in the Odes. Most of the examples involve risings and settings as guides to the time of year, and most are within the range of the phenomena mentioned in Hesiod’s Works and Days. But in Odes 3.29.17-20, for the special interest of Maecenas, Horace breaks new ground by drawing more topical material from the Julian calendar, to remind his friend that it is now July and too hot for working in Rome: the (evening) rising of Cepheus on the 9th, the (morning) risings of Procyon on the 15th and Regulus on the 29th, and the entry of the sun into Leo on the 17th. Such an array of calendaric lore is clearly designed to appeal to Maecenas, who must have had a particular interest in astronomical phenomena.

The Julian Calendar and the Problem of the Equinoxes in the Early Middle Ages

2018 ◽  
Author(s):  
C. Philipp E. Nothaft
Keyword(s):  
Middle Ages ◽  
Eleventh Century ◽  
Medieval Literature ◽  
Seventh Century ◽  
Observational Methods ◽  
Early Medieval ◽  
Early Middle Ages ◽  
Julian Calendar ◽  
Medieval Europe ◽  
Solar Astronomy

This chapter familiarizes readers with the ancient back-story of the Julian calendar and describes how one of the central problems inherent in this calendar—the drift of the equinoxes and solstices caused by an overestimation of the length of the tropical year—manifested itself in medieval literature until the end of the eleventh century. It also explores how the development of the computus genre in seventh-century Ireland was instrumental in preserving knowledge of the Western calendar’s Roman-pagan roots. The final two sections show how the existence of diverging traditions for the dates of the equinoxes and solstices in the Julian calendar created an important context for the practice of solar astronomy in early medieval Europe, which included the use of observational methods.

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