THIS is the spectacular sight which greeted hundreds of stargazers who flocked to Scotland yesterday to catch a rare glimpse of an annular eclipse of the sun.
The annular eclipse was also visible in the Arctic and North Atlantic.
RING OF FIRE: The annular eclipse as seen from Caithness; Picture: BOBBY NELSON
Although historical non-scientific reports of annular eclipses may date back to the ancient Greeks, neither Ptolemy nor his followers in the medieval period refer to them.
Even if some annular eclipses were observed and recorded, they were not available to, or for some unknown reason were neglected by, Ptolemy.
Stephenson has identified three convincing direct allusions to annular eclipses in historical medieval sources (nos.
Firstly, some astronomical and optical considerations can be taken into account to explain the rarity of credible reports of annular eclipses.
As discussed, the Ptolemaic tradition leaves no room for the possibility of annular eclipses and this will have influenced observers.
Despite this, the reports of two annular eclipses in the medieval period (nos.
Therefore, we conclude that both astronomical considerations and historical conditions acted in such a manner to make it difficult to observe, define, or justify the phenomenon of annular eclipses.
In this view an annular eclipse was possible when the Moon is near its apogee, and, inversely, the Sun was close to its perigee.