tag:blogger.com,1999:blog-7752626037671660516.post1254282850102992298..comments2021-01-20T09:22:07.084+00:00Comments on Astrolabes and Stuff: Drawing up a medieval horoscopeSeb Falkhttp://www.blogger.com/profile/12749635113622688649noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-7752626037671660516.post-19799995429572298882017-04-13T14:48:54.905+01:002017-04-13T14:48:54.905+01:00Hi Anthony,
Thanks for your question (and apologie...Hi Anthony,<br />Thanks for your question (and apologies for the delay in replying. The mathematics behind these house divisions is quite well understood (unlike the precise details of the calculation methods), though different astrologers used different ways of dividing the houses at different times. As you may be able to tell, the mathematics is a bit of a struggle for me, but it's explained very well in a book by John North, "Horoscopes and History" (1986), from which I took the diagram above. <br /><br />The division is clearly dependent on latitude, and it would have been very problematic near the poles (the formula I used breaks down above about 66°, because I'm asking it to work out the arcsin of a number greater than 1, but I should stress that my formula is a very rough modernization of medieval methods). I'd like to think that an astronomer who could compute houses would have understood the limitations of the procedure, but I'm sure there were people who went through a process step by step without really understanding what all the numbers represented.Seb Falkhttps://www.blogger.com/profile/12749635113622688649noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-50435052321595532422017-04-07T07:34:03.267+01:002017-04-07T07:34:03.267+01:00Dear Seb:
Can you please give us more details on t...Dear Seb:<br />Can you please give us more details on the mathematics behind how these tables of houses were constructed? Precious little has been written on this subject<br /> From what I know, some house systems fail to work close to the polar regions. Were the medieval computers of tables of houses aware of such a limitation, or was their method free from such problems?<br />Yours, &c<br />Anthony. Anthony L .https://www.blogger.com/profile/05996415947736110422noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-66236748887010278262017-04-07T07:31:05.934+01:002017-04-07T07:31:05.934+01:00This comment has been removed by the author.Anthony L .https://www.blogger.com/profile/05996415947736110422noreply@blogger.comtag:blogger.com,1999:blog-7752626037671660516.post-2352342330326681202015-06-03T09:35:29.723+01:002015-06-03T09:35:29.723+01:00a great example of casting horoscopes in 15th cent...a great example of casting horoscopes in 15th cent London is at http://iris.ucl.ac.uk/iris/publication/61029/1<br />Sophie Page on Richard TrewythianPeter Jonesnoreply@blogger.com