An astronomical determination of the turbidity parameters of the atmosphere

1989 ◽  
Vol 41 (1) ◽  
pp. 13-18
Author(s):  
G. Asteriadis ◽  
A. C. Tsioumis
Keyword(s):  
Astronomical Determination

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

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.

Twentieth-Century Longitude: When Greenwich Moved

2019 ◽  
Vol 50 (2) ◽  
pp. 221-248 ◽  
Author(s):  
Michael Kershaw
Keyword(s):  
Twentieth Century ◽  
Historical Context ◽  
World War ◽  
Current Standard ◽  
Royal Observatory ◽  
The First World War ◽  
First World ◽  
Astronomical Determination ◽  
Universal Reference

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.

Automation of the astronomical determination of the universal time

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