Discussion Of Observations Of The Transits Of Venus In 1761 And 1769

Published in 1900, this volume is part of a series detailing the observations and findings of the transits of Venus in 1761 and 1769. The author, Simon Newcomb, was a renowned astronomer and mathematician who contributed significantly to the study of celestial mechanics. This work is of historical importance and will interest scholars and enthusiasts of astronomy and the history of science. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

As one of the oldest scientific institutions in the United States, the US Naval Observatory has a rich and colourful history. This volume is, first and foremost, a story of the relations between space, time and navigation, from the rise of the chronometer in the United States to the Global Positioning System of satellites, for which the Naval Observatory provides the time to a billionth of a second per day. It is a story of the history of technology, in the form of telescopes, lenses, detectors, calculators, clocks and computers over 170 years. It describes how one scientific institution under government and military patronage has contributed, through all the vagaries of history, to almost two centuries of unparalleled progress in astronomy. Sky and Ocean Joined will appeal to historians of science, technology, scientific institutions and American science, as well as astronomers, meteorologists and physicists.

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1875 edition. Excerpt: ... CHAPTER III. THE TRANSIT OF 1769. The general impression among astronomers, after the observations of 1761 had been discussed, was that too much reliance had been placed on Delisle's method. ' Experience, ' wrote J. D. Cassini, later, in his ' Histoire du Passage de 1769, 'is our chief instructor; the fruit of its lessons indemnifies us for the value of the years they cost us. The principal end had been missed, in 1761, for want of observations in places where the durations differed sufficiently. It was essential not to experience a second time the same disadvantage.' Among the first statements published respecting the transit of 1769 was that by the ingenious Ferguson, who wrote as follows in 1762: ' On the 3rd of June, in the year 1769, Venus will again pass over the sun's disc, in such a manner as to afford a much easier and better method of investigating the sun's parallax than her transit in the year 1761 has done. But no part of Britain will be proper for observing that transit,1 so as to deduce anything with respect to the sun's parallax from it, because it will begin but a little before sunset, and will be quite over before two o'clock next morning. The apparent time of conjunction of the sun and Venus, according to Dr. Halley's tables, will be at thirteen minutes past ten o'clock at London, at which time the geocentric latitude of Venus will be full ten minutes of a degree north from the sun's centre; and therefore, as seen from the northern parts of the earth, Venus will be considerably depressed by a parallax of latitude on the sun's disc; on which account the visible duration of the transit will be .lengthened; and in the southern parts of the earth she will be elevated by a parallax of latitude on the sun, which will shorten...

The Sun is nowadays observed using di?erent techniques that provide an almost instantaneous 3-D map of its structure. Of particular interest is the studyofthevariabilityinthesolaroutputproducedbythedissipationofm- netic energy on di?erent spatial and temporal scales – the so-called magnetic activity. The 11-year cycle is the main feature describing this phenomenon. Apart from its intrinsic scienti?c interest, this topic is worth studying because of the interaction of such processes with the terrestrial environment. A ?eet of space and ground-based observatories are currently monitoring the behaviour of our star on a daily basis. However, solar activity varies not only on this decadal time-scale, as has been attested mainly through two methods: (a) records of the number of sunspots observed on the solar surface from 1610, and (b) the records of 14 10 cosmogenic isotopes, such as Cand Be, measured in tree-rings and i- cores, respectively. The study of the long-term behaviour of solar activity may be comp- mented by the study of historical accounts describing phenomena directly or indirectly related to solar activity. Numerous scienti?c and non-scienti?c d- uments have reported these events and we can make use of them as a proxy of solar activity in past times.

The Viennese Jesuit court astronomer Maximilian Hell was a key figure in the eighteenth-century circulation of knowledge. He was already famous by the time of his celebrated 1769 expedition for the observation of the transit of Venus in northern Scandinavia. However, the 1773 suppression of his order forced Hell to develop ingenious strategies of accommodation to changing international and domestic circumstances. Through a study of his career in local, regional, imperial, and global contexts, this book sheds new light on the complex relationship between the Enlightenment, Catholicism, administrative and academic reform in the Habsburg monarchy, and the practices and ends of cultivating science in the Republic of Letters around the end of the first era of the Society of Jesus.