steven wrote:Deb quoted Ptolemy:

?Assume first that the beginning of Aries is rising, so that the beginning of Capricorn is at midheaven?

?In the same way, let the beginning of Aries be setting, so that the beginning of Cancer may be at midheaven and the beginning of Gemini may be removed from the midheaven above the earth in the direction of the leading signs ??

Needless to say, I must really point out that "the beginning of Aries" is 0 Aries. The "beginning of Cancer" is 0 Cancer. The "beginning of Gemini" is 0 Gemini! The only equal division in his words is that of whole sign!

I can see the logic of your arggument But one of the hallmarks of Ptolemy?s work is that he does refer to specific degrees when he talks about the orient, occident and midheaven. In the next paragraph of that example he tells us to assume that the beginning of Aries is not on the angle and that the 18th degree of Taurus is on the midheaven. There are other passages where Ptolemy appears to define the midheaven and the ascendant as the specific degrees, and the associated parts/houses as the 12th-part that is succeeding to this degree. As Martin says, what we might translate as sign, we might also translate as house (and vice versa). But whichever way we look at this it is thorny issue, so I don?t want to add to any misinformation and leave the impression that I *know* exactly what was intended here! (The point of my earlier post was only to say that if I had to pick a system based purely on the available text, I would have to say equal and I do not see how anyone can claim that the whole sign argument is proven in this text).

But I am very much in agreement with Steven generally, especially in the belief that too much is made of ambiguous references that are not capable of being proven one way or another. I sometimes wonder what Ptolemy would have made of these kinds of discussions ? and whether he was actually like Kepler and didn?t care much for the houses ? whichever way they were divided! In order to understand a technique it surely makes more sense to refer to sources which were clear and unambiguous. That is why I am more persuaded by the references found in contemporary works. A definition of the houses as given by Antiochus, for example, suggests that even if the references discussed above do suggest equal house division, there was more to the system than might meet the eye in Ptolemy?s work:

Each of these 12 places obtains as its lot the 5 pre-ascended degrees and the 25 post-ascending degrees, if the squares [ie, the angles] should occur through ninety degrees. But if they should occur with different numbers of degrees, divide the degrees of the square numbers equally into three parts, and you would know how many degrees each place of the zodiac has. (The Thesaurus, ch.46).

With regard to the use of whole-sign alongside quadrant division ? it makes perfect sense to me that in an age where accurate time was a rarity, where there were no computers to quickly refer to, and where tables were expensive and rounded up, a rough and ready approach was all that made sense in many situations, but that this would be employed alongside a more theoretically precise approach for important calculations. One thing that strikes me is that there are many reminders of the need to calculate by degree to be correct, and to not rely upon signs equating to houses, but there is not one ancient authority reminding us that the correct approach is to simply associate the places with the signs. In other words, no ancient astrologer gives instruction on how to divide the houses by the whole sign method, as many modern astrologers are now doing, (and so leaving the impression that this was always the theoretically correct thing to do).

Well I agree (of course!), but at the same time let?s not underestimate the reality of practical convenience. For example, when modern astrologers are taught chart calculation they are expected to correct the planetary positions to the minute, but we only have to go back to the 17th century to see a very different approach. Where Lilly teaches chart calculation in Christian Astrology, he tells the student that the noon position of the planets will suffice for most situations, so long as we remember to correct the Moon?s position by adding 3? for each 6 hours that passes. So a job that a modern astrologer might expect to take a fair bit of time can actually be done in about 30 seconds. It?s a tradesman?s cheat, but it makes a lot of sense in those situations where the judgement won?t benefit from more precision, and where the hour of birth may be a ?guestimate? anyway. This is a workable thing to do in most situations, so long as we remember that there are some occasions when we need to take more trouble and do the job properly. I am not taking anything away from the point you made or denying that whole-sign can be valid, but it also seems to me that the classical ?reminders? about calculating by degree ought to be seen in this sort of context too. At least I think we ought to remain wary of this being a relevant consideration, because we so easily lose sight of the practicalities of early chart construction now that all we have to do is moan about the computer crashing

I'm not an expert about house domification and maths makes me crazy, but I believe that many Renaissance astrologers followers of Ptolemy used what is in fact called Placidus method.

But it was very old if it is quoted by IbnEzra in Liber de rationibus tabularum:

"Secundum hoc differentia que est a principio 10me domus ad principium 11me in tabula circuli recti, erit duarum horarum temporalium secundum horas temporales gradus principii 11me, 2. et erit differentia ascensionum inventarum ante principium 11me ad ascensiones orientis in tabula terre, tamquam 4 hore temporales secundum gradum principium 11me".

In a few words every house is 2 hours, so Ibn Ezra says the difference between the tenth house and 11th is 2 hours and from the 11th to the East are 4 hours.

But they don't quote Tetrabiblos as reference, they quote Almagest.

Margherita

Gjiada wrote:I'm not an expert about house domification and maths makes me crazy, but I believe that many Renaissance astrologers followers of Ptolemy used what is in fact called Placidus method.

While it is true that ibn Ezra favoured house division by double temporal hours, the method later propounded by Placidus, I am not aware of anyone else using it before the 17th century. The medieval standard system was Alcabitius, gradually giving way to Regiomontanus during the Renaissance.

Martin Gansten wrote: While it is true that ibn Ezra favoured house division by double temporal hours, the method later propounded by Placidus, I am not aware of anyone else using it before the 17th century. The medieval standard system was Alcabitius, gradually giving way to Regiomontanus during the Renaissance.

It could be, I'm not the expert.

I just meant that Placidus -and Argoli who mentions Placidus tables and calls them Ptolemaic Tables - claims that this house domification is the same used by Ptolemy, the same method mentioned in the second book of Almagest.

This is - I'm sure because I know that group quite well - the house system they use in CieloeTerra, Bezza's group, and they practice just Ptolemy's astrology. They surely do not use neither equal houses or whole signs houses, this you can take for granted.

Have a Merry Christmas Margherita

Gjiada wrote:I just meant that Placidus -and Argoli who mentions Placidus tables and calls them Ptolemaic Tables - claims that this house domification is the same used by Ptolemy, the same method mentioned in the second book of Almagest.

Yes, Ptolemy would have been surprised at the opinions Placidus ascribed to him. The Almagest is not about astrology, although fans of both Alcabitius and Placidus houses (and perhaps others?) have tried to relate their favourite systems to that text.

This is - I'm sure because I know that group quite well - the house system they use in CieloeTerra, Bezza's group, and they practice just Ptolemy's astrology. They surely do not use neither equal houses or whole signs houses, this you can take for granted.

I am sure you are right about Bezza et consortes using Placidus houses; but if so, they are definitely not doing 'pure' Ptolemaic astrology. Indeed, it would be quite difficult to do so, as Ptolemy is a most incomplete guide for a practising astrologer. Even Placidus had to fill in the lacunae with his 'Reason' (of a late-scholastic, Aristotelian kind).

Have a Merry Christmas

And you!

Martin Gansten wrote:[I am sure you are right about Bezza et consortes using Placidus houses; but if so, they are definitely not doing 'pure' Ptolemaic astrology. Indeed, it would be quite difficult to do so, as Ptolemy is a most incomplete guide for a practising astrologer. Even Placidus had to fill in the lacunae with his 'Reason' (of a late-scholastic, Aristotelian kind).

In fact my secret idea about them is they follow Placidus more than Ptolemy.

Have a nice Christmas Margherita