The Twilight Factor in Ancient Astrology

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In the 'Is a retrograde planet really weak?' thread Deb wrote in reply to a quote from Olivia:
As far as I'm aware, a chart will turn from being diurnal to nocturnal in an instant, just as the 12th diurnal (seasonal) hour will move into the 1st nocturnal hour in an instant. I think that modern astrologers try to add in a twilight factor but that seems to me to contradict the ancient approach to this matter.

http://skyscript.co.uk/forums/viewtopic ... 3&start=30

I've been wondering about this for a long time and now seems like a good time for a topic thread concerning it. Is Deb following a common current assumption or do the ancients come out and say this? I don't remember coming across explicit references to it in ancient works, but then I'm not particularly well read in ancient astrology. Please, who wrote about it and in what work(s)?

Also, it's possible to have the Sun zodiacally placed above or below the horizon in a chart, but yet the altitude shows that it's actually several degrees into the other hemisphere. Are there specific references to this in ancient astrology? Did the ancients document that they looked at the zodiacal degrees involved and always treated the Sun in an earlier degree as above the horizon and diurnal and in a later degree as below and nocturnal. Or did they caution to always take the altitude in consideration. Again, who wrote about it and in what work(s)?

Re: The Twilight Factor in Ancient Astrology

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Kirk wrote: Also, it's possible to have the Sun zodiacally placed above or below the horizon in a chart, but yet the altitude shows that it's actually several degrees into the other hemisphere.
Hi Kirk,
as the Sun has never ecliptical latitude he is always in the ecliptic. Thus his mundane and his ecliptical position in longitude are identical and this problem is not existing because the ascendant (and the descendant) is defined as intersection of horizon and ecliptic.

Johannes.

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Oh dear ... I did get myself confused when I quickly added on the 2nd part about the Sun in relation to the horizon! I was thinking of the other bodies, which do have latitude. Thanks for clearing that up, Johannes.

So anyway, that leaves us with the first matter: On-and-off for day and night or more gradual. I've been rummaging around for something I saw months ago which I believe was from the 17th century. That's not ancient but it's quite a few steps back. What sticks in my mind is a statement in someone's book which surprised me at the time that one should consider a chart to be nocturnal when the Sun was approaching the Descendant within a certain number degrees. I'm thinking it was Ramesey, Partridge or Coley, but I haven't found it yet. Or maybe it was later in Sibly. The person who wrote it may have gotten it from an earlier source ? or 'modern' was creeping in.

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Sorry that I can't quote a classical text now but I think it better than having no quotation at all, I give a text of today. To avoid thread hopping I copy my answer to Deb and Olivia in the spring-thread here again (and I hope with the permission of the moderators).
johannes susato wrote:
Deb wrote:
As a rule, if it's within 12 degrees of the ascendant, it's still a daytime birth. There are exceptions, but not too many.
Hi Olivia,
I wonder if you can offer a reference to that rule.
Hi Deb, hi Olivia,
I just find the 'real' astrologer John Frawley saying - The Horary Textbook, p. 48 -:
"Allow a few degrees in favour of day at either end [of the AC-DC-line], so if the Sun is only a couple of degrees below the Ascendant or the Descendant you count it as day. This is because the Sun's light is visble before the Sun rises and after it sets. 'A few' is all the precision necessary here: the precise number varies with latitude and time of year."
This definition seems to be rather imprecise and in reality a maceration of the classical definition of day and night, a contradiction to it as Deb has already stated above.

Regards
Johannes

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I'm now completely confused about the double thread too. Sorry - I posted this in the other thread because I was answering a comment there, but I will copy it over to this thread too. I don't have much more to add to this. I don't think we will find quotes saying "the moment of sunset is the actual official moment of sunset" in the ancient texts, because why would they? If they didn't do this, then we ought to be able to point to an ancient text that makes use of sect, which says otherwise, don't you think?* (see edit below)

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My point is this: ancient astrologers didn?t just speculate about the moment of sunrise and sunset, they worshipped it, and they observed it religiously (or attempted to) in order to define it to a moment. The whole philosophy of sect is intimately bound to the concept of the seasonal hours, and assumes the belief that one planet?s hour represents a very different quality of time than the next planetary hour; and that the daytime hours are very different from the night time hours. We move from a day time hour to a night time hour in an instant and in that instant the chart changes from being a diurnal chart to nocturnal one. It is at this moment that sect alignments change, and I don?t believe it is philosophically justified or practically convenient to bring in a fudge factor to recognise twilight, be it nautical, civil or astronomical.

As the planetary recording of time changes from diurnal to nocturnal, that is when the definition of the chart changes ? that is all I am saying; not that twilight doesn?t have a certain quality of its own. It might be argued that the planetary hours don?t mean much in modern astrology, but they certainly did in ancient astrology, which is where the concept of sect is most deeply embedded. But yes, twilight has a different quality; that is another issue. On the other hand I have sat and watched the sunset, doing nothing else but sitting and observing the sunset, and there is ? very definitely ? a single moment when the energy changes; when the last remnant of the Sun's disc dissapears. The only time I have been able to see the same effect with sunrise was when I was in an airplane and I was watching the sun slowly rise over the a widespread horizon. The moment it actually rose was startling, because the whole horizon glittered, in the same way that a total eclipse glitters for a moment in its diamond effect. That is when I understood why it was such a sacred and religious moment, and that we can?t expect to spread its magic out to some extended period of time when the light is increasing or fading.

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I am editing this post to say that a clear definition of what constitutes daytime and night time is given in Ptolemy's Almagest, at the start of chapter VIII - the chart becomes diurnal as the Sun becomes exact with the local horizon.
Last edited by Deb on Fri May 29, 2009 10:19 pm, edited 1 time in total.

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Deb wrote:On the other hand I have sat and watched the sunset, doing nothing else but sitting and observing the sunset, and there is ? very definitely ? a single moment when the energy changes; when the last remnant of the Sun's disc dissapears.
This ties in with Kirk's earlier question about zodiacal degrees, because, although the Sun never has latitude, it is (as Deb says) a disc rather than a point, and the moment of its leading edge rising/trailing edge setting is different from the rising/setting of its centre, which is where we measure its zodiacal position. Also, if we want to keep things observational, we have to include the effects of atmospheric refraction (http://en.wikipedia.org/wiki/Atmospheric_refraction).

I have no idea what ancient authors wrote on this topic (if they wrote anything at all), although personally I'm inclined to agree with Deb about using the visible rising/setting of the Sun's edge. Certainly the ancients did seem to feel that everyone is born either by day or by night, which would mean that the change occurs in a moment.

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As this has nothing to do with a retrograde planet being weak I will post only here. I started this thread so as not to lose one topic within another: I was aiming for a clear day/night approach rather than a twilight blend.


Deb wrote:
. . . ancient astrologers didn?t just speculate about the moment of sunrise and sunset, they worshipped it, and they observed it religiously (or attempted to) in order to define it to a moment.
'Worship' sure sounds out of place to me ? kind of like a trombone in the middle of the violins (I can't resist these things). Perhaps I'm wrong, but the idea of Ptolemy or Dorotheus 'worshiping' a natural phenomenon seems starkly counter to their rational use of astrological symbolism. There was plenty of such worshiping in the ancient world, but the sense of worship doesn't seem present in the ancient astrological works. They were people of a different philosophical bent, already influenced by the approach and interests that would later develop into science as we know it.


Deb wrote:
On the other hand I have sat and watched the sunset, doing nothing else but sitting and observing the sunset, and there is ? very definitely ? a single moment when the energy changes; when the last remnant of the Sun's disc dissapears.
Martin wrote:
Certainly the ancients did seem to feel that everyone is born either by day or by night, which would mean that the change occurs in a moment.


But that moment is lost to us as we sit looking at our charts. Martin mentioned refraction, but it's a much larger matter than that. Our normal method of chart calculation only works where the land is flat ? like Alexandria or along the Tigris and Euphrates. It's different in a mountainous region. If you're at the base of the west slope of a tall mountain (think of Switzerland) you're going to have to wait for your sunrise. If you are 10 miles further west of that mountain you will have an earlier sunrise. Imagine what happens if you are in a valley with mountains around you! The mountains don't even have to be massive to have an effect. I grew up with a small mountain of around 1000-1200 feet about 2 miles to the east of the house. I used to imagine looking through the base of the mountain to where the true horizon was. That mountain definitely affected our time of sunrise. The people who lived on the east side toward the top had a spectacular view of a wide valley and the Cascade Mountains miles off in the distance. They got their sunrise before us, yet they lived not at all far from us 'as the crow flies'.

This isn't accounted for in charts and can be easily overlooked in order to make ancient astrology easier and more convenient to work with. We want choice A or choice B, diurnal or nocturnal. But to be truly accurate you need to be at the location if you want the time the Sun rises there, or you need to be able to take the topography into account in your calculations. An astrologer next to that Swiss mountain is going to know that the sunrise shown by the astrology software isn't going to be the sunrise that is experienced. The theories don't match experience and reality, so do we really want to stick too closely to them?

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Deb wrote:On the other hand I have sat and watched the sunset, doing nothing else but sitting and observing the sunset, and there is ? very definitely ? a single moment when the energy changes; when the last remnant of the Sun's disc dissapears.
Truly beautiful, however, I would keep the matter simple and observe how the Solar centre is related to the rational horizon. There is a 'twilight' to all things but somewhere in between there is a rational midpoint that we use as a rational point of reference, per definition.
http://www.astronor.com

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As I use geocentric positions of the planets I feel the most comfortable with the use a geocentric definition of the horizon. Therefore the latitude of the birth place has to be converted from geographic to geocentric longitude, http://www.coyotegulch.com/articles/Tim ... _fig04.png
http://www.coyotegulch.com/articles/Tim ... a0001.html
This latitude is slightly (a few arc minutes) off, therefore the Ascendant is also slightly different.

The horizon then can be defined as the plane through the center of the earth perpendicular to the axis geocenter-person.

This is a very geometrical approach but it's the one I prefer the most in astrology. As it's geocentric the question of twilight wouldn't play a role in a literary sense. The same plays with relating astrology with local seasonal events, they don't play a role in the earth's center but I do find this an attractive approach though.
I therefore sometimes are in dubio :? . However the aspects and transits as measured along the tropical (in the sense of geometry) ecliptic usuallly convince me of the value of the geometrical approach.

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The other thread that Mark started earlier has some very interesting points, but I have now locked that to prevent the discussion going all over the place. I very much liked Osthanes final post, although I'm a little hesitant about his final comment where he writes:
Comparing the childbirth, I would say the moment when his full disc is visible. A child can be said to be born really when it has fully left the body of the mother. On the other hand, a person has to be claimed to be alive if there's even the tiniest sign of life. To further adapt this logic, I would say the a person arrives my home in the very moment when he successfully crosses the threshold, and he leaves when I can close the door behind him.
To sum up, I think astrologically we can say it's daytime when the full disc of the Sun is visible, and it's night when the full disc disappeared. Certainly, this model may be argued or questioned, and also, it doesn't answer whether we should totally rely on apparent rise (that is, we should work with topocentric perspective, apparent horizon and reckon in refraction).
What follows relates to that, and some points that Steven made in the earlier thread, and to what Kirk has referred to above.

If I were speaking purely from a personal observation point of view, ?true sunrise?, for me, would be the moment that the disc makes its first visible appearance in my local horizon, whilst ?true sunset? would be the moment that the very last glimpse of the disc disappears (ie, what I can see with my own eyes). But as Kirk says, it is impossible and impractical to take that position as an astrological theory. Ptolemy discusses this sort of problem in chapter 8 of the Almagest, where he points out how it is utterly impossible for astrologers to try to determine the exact moment of a rising because the different landscape features of different local horizons means that every locality differs at every time. Sunrise in one house, would be at a different time from the house next door with the higher fence.

So we are not working with observed appearances, we are dealing with astronomical averages, and we take the time of rising for a locality in general, without worrying about whether or not the disc of the Sun is actually visible at the specific location of birth.
Once we accept that, it seems very easy to realise that ? since we are not dealing with the actual visible observance of the phenomena ? we can talk about the ?true rising? being the one in which the centre of the Sun aligns with the ascendant, not the upper or lower part of the disc, or any part of the light before or after it. This is entirely in accord with the procedure taken to determine the (invisible) moment when a star or planet experiences a heliacal rising. It is the conjunction of the star with the centre of the Sun, not the edge of it. Ptolemy describes this but he certainly didn't invent the notion, because he is merely explaining the procedure given in many older texts.
Also, it is because the Sun was known to be a disc and not a point that the allowance of 16? was used in the determination of cazimi. The disc was judged to be 32 minutes in width, so if a planet is within 16? of it on either side then it was assumed to be actually touching the disc of the Sun and not just obliterated by its light. But even so, the centre - the actual heart of the power - is still the centre of the disc.