fol 70r Star-hours & months ~ for the mathematicians

In yesterday’s post  I ended by referring to the marine dog-and-phoenix used as headers in Brouscon’s  ‘Breton Tables’.

See Nautical Alamanac, and Portolan chart of Guillaume Brouscon (Fr. 1543).

Here is his chart for March, from the star-hour tables, or ‘star clock’ (fol12)

I think it is possible that the same numerical keys are embedded in the inner, patterned row around the centre of fol.70r, using some sort of tally-mark system.

I suggest this because, taking the ‘cross’ to mean a terminus ~ as it is used in other astronomical diagrams in the manuscript – gives thirteen divisions.

Brouscon’s chart is formally divided into sixteen divisions, but three  are left blank  ~ thirteen again.

Among those thirteen on Brouscon’s chart, one is shaded as a doubled section.

And on the chart from fol.70r (as far as I can tell from the so-so copy), one of the divisions is doubled.

Any maths. whiz who’d like to offer some  insight on possible relationship between the inner ring and Brouscon’s chart?

The ‘fishes’ in the middle of Brouscon’s chart below are not original, of course; they are there to distinguish this ‘original art’.  🙂

(I”m fairly sure the  ‘ladies’, are personified stars and in this case hour stars, with a multi-lingual pun implied, part of which is the Koine (Hellenistic Gk) , ὡραῖος [hōraios],  from the classical Greek ὥρα or ‘hour’ ~ also linked by etymology  to the Greeks’ idea of  beauty – considered as that appropriate for one’s present time in life. The word ‘hour’ appears in Middle English during the 13thC AD.)


PS – I thought I’d keep the post simple, and only refer to Brouscon’s chart, but it seems  fair to mention that if it were supposed that the top-centrre figure were Polaris, the remaining star-holders would be 28 –  the full number of manazil.

I say ‘full number’ because for mathematical calculations the Indian (and thus the Muslim Islamic) habit was to reduce the number to a formal 27.


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