Public and scientific time at Paris Observatory : evolution over three centuries
Abstract
When the Académie Royale des sciences is created in 1666, and the following year the Observatoire Royal, by Louis the XIVth, several improvements had appeared during the past millenium. Time and determinations by sundials, between sunrise and sunset had led to intervals of twelve unequal hours and to a special reference, the time the shadow was the shortest one, later known as to represent the meridian line. The two aspects of time were also seen : - the date as an instant of time ; - the duration between two dates.
- Publication:
-
Journées 2005 - systèmes de référence spatio-temporels
- Pub Date:
- October 2006
- Bibcode:
- 2006jsrs.conf...54D
- Keywords:
-
- Earth rotation;
- reference systems;
- relativity;
- time;
- ephemerides