Heron's Dioptra 35 and Analemma Methods: An Astronomical Determination of the Distance between Two Cities

Centaurus ◽  
2005 ◽  
Vol 47 (3) ◽  
pp. 236-258 ◽  
Author(s):  
Nathan Sidoli
1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.


2014 ◽  
Vol 31 (1) ◽  
pp. 59-73
Author(s):  
Refik Güremen

Abstract It has often been argued, in scholarly debate, that Aristotle’s denial of citizenship to the working population of his ideal city in Book VII of the Politics constitutes a fundamental injustice. According to this view, although it is true that their way of life prevents them from living a morally virtuous life, it does not follow that the working people are naturally devoid of the human qualities required for such a life. So, rather than finding a just way to distribute citizenship among the diversity a city’s population would naturally exhibit (as he does, to a certain extent, in Book III), Aristotle would commit himself to oligarchic measures in Book VII. In this article, it is argued that the main concern of Book VII is less with a just determination of the extent of citizenship (unlike Book III) than with conceiving the most efficient way for a city to be happy: this consists in establishing a community composed of individuals who lay claim to happiness in the same way and to the same degree. In other words, it consists in reducing the diversity of Book III to a certain kind of homogeneity.


2019 ◽  
Vol 50 (2) ◽  
pp. 221-248 ◽  
Author(s):  
Michael Kershaw

By the beginning of the twentieth century, the meridian passing though the Royal Observatory at Greenwich had become a near-universal reference for place and time. It was the zero of longitude. But our current standard of zero longitude is about 100 metres away from the original. That mobility needs historical context: Greenwich began to move in the years after the First World War, when wireless techniques for the astronomical determination of longitude and the standardisation of time were developed, and has carried on moving ever since. In this article, I describe how twentieth-century techniques for the determination of longitude not only brought improved precision but also led to fundamental changes in our long-standing conventions of longitude. And I show how – despite its mobility – our current standard of zero longitude continues to respect the original.


1989 ◽  
Vol 32 (4) ◽  
pp. 350-351
Author(s):  
M. K. Abele ◽  
V. A. Gedrovits ◽  
K. K. Lapushka ◽  
L. F. Roze

1998 ◽  
Vol 30 (8) ◽  
pp. 1445-1460 ◽  
Author(s):  
J Burgess ◽  
C M Harrison ◽  
P Filius

This paper presents a comparative analysis of how representatives from the public, private, and voluntary sectors of two cities [Nottingham (United Kingdom) and Eindhoven (The Netherlands)] responded to the challenge of communicating more effectively with citizens about issues of sustainability. The analysis is set in the context of literature about the need to widen participation in the determination of Local Agenda 21 policies, and the drive for more inclusionary forms of communication in planning and politics. Workshop members discussed the results of surveys and in-depth discussion groups with local residents which had revealed considerable scepticism and mistrust of environmental communications and environmental expertise. Three themes are explored. First, there is consensus in attributing responsibility for public alienation and resistance to environmental communications to the content and styles of media reporting. Second, there are contrasting discursive constructions of the ‘public’, which reflect different political cultures—with the Nottingham workshop supporting a strategy to share power and knowledge more widely than hitherto, whereas the Eindhoven strategy proposed greater rigour, clarity, and authority from the local state. Third, responding to evidence of public resistance to calls for more sustainable practices, workshop participants in both cities focused on what institutions themselves can and should do to progress environmental goals. Workshop participants in both countries acknowledged the urgent need for public, private, and voluntary sector organisations to match their own practices to their environmental rhetoric.


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