Posted: Mon Sep 01, 2008 2:42 pm
He doesn't appear to suggest this in Tetrabiblos. The first source I remember making that point is Cardano in the Seven Segments. However, it must be an older idea than that? I will check Liber Hermetis and Ibn Ezra.Did Ptolemy differentiate in influences gather from north or south of the ecliptic?
While the visible colour of a star often seems to reflect its traditional nature very well I am not sure that is always the case. I have read a secondary source that claims Cornelius Agrippa was the first astrologer to quite explicitly suggest star influence was entirely based on their colour.I think that Ptolemy considers stars according their magnitude and colour. For example red stars have generally Mars nature and the more brilliant ones the nature of Jupiter and so on. For example Sirius, white with a reddish nuance, has a Jupiter-Mars nature and Aldebaran is red so it has a Mars nature.
It seems likely traditional observations of stars effects were passed down in sources now lost to us. These probably also contributed to Ptolemy's associations. This kind of practice was still going on up to the time of Lilly when he suggested the nature of Algol was more like Mars-Saturn rather than Saturn-Jupiter as suggested by Ptolemy.
Incidentally, Sirius has a generally whiteish colour. However, in some atmospheric conditions it appears blue. Near the horizon line , it often appears to the naked eye be flashing with white, blue and red hues.
Ptolemy did seem to suggest Sirius had a red hue. Books VII and VIII of Ptolemy?s Almagest contain one of the earliest and most famous of the ancient star catalogs, in which Ptolemy lists the positions and brightness of some 1022 stars. He comments on the colour of only six of these stars?Betelgeuse, Aldebaran, Pollux, Arcturus, Antares, and Sirius?and assigns the color red to each. In particular, for Sirius in the constellation Canis Major, he states its location, on the dog?s mouth, as well as its relative brightness and color: bright and red.
The whole issue of a 'red Sirius' has stirred quite a debate amongst astronomers. The general conclusion is that Ptolemy was not accurate but there is evidence to the contrary. For example Aratus, the orator Cicero, and general Germanicus all suggested the stars colour was red. Seneca, too, had described Sirius as being of a deeper red colour than Mars. Outside Europe, The Dogon tribe has a legend the star Sirius was originally red.
However, not all ancient observers saw Sirius as red. The 1st century AD poet Marcus Manilius described it as "sea-blue", as did the 4th century Avienus. It is the standard star for the color white in ancient China, and multiple records from the 2nd century BC up to the 7th century AD all describe Sirius as white in hue. The Japanese called Sirius 'The blue star' to differentiate it from 'The red star' (Aldebaran).
The whole topic remains controversal since while astronomers accept a stars magnitude can fluctuate considerably the idea that its colour could change from red to white/blue contradicts the current understanding of the life cycles of stars.
Because of the different ways the naked eye can perceive stars and due to the effects of atmospheric conditions some astrologers started to use the more objective standard of star spectra from astronomical observation of the light emitted by stars. One of the first to do this was Johndro, in his book ?The Stars: How and Where They Influence? (1929) . The most recent attempt to do this was in George Noonan's book 'The Fixed Stars & Judicial astrology' (1990). Noonan noted that the traditional associations very often co-incided with the spectra of stars. However, there were some variations. In any case, many astrologers would probably be uncomfortable abandoning the tradition of naked eye observation of stars in favour of an astronomical Spectrometer.
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