Skyscript Astrology Forum

I found these series of highly informative posts by Rumen Kolev on the heliacal appearance of planets (Phaseis) in babylonian , hellenistic and medieval astrology.

I thought it was extremely interesting so I am sharing the link from the
ACTastrology.com website.

http://actastrology.com/viewtopic.php?f=4&t=34&start=0

Thanks, Mark C

MarkC wrote:I found these series of highly informative posts by Rumen Kolev on the heliacal appearance of planets (Phaseis) in babylonian , hellenistic and medieval astrology.

I thought it was extremely interesting .

Hello, it's really very interesting.

Planets' phases are very important especially in Ptolemy, who judges about everything considering what he calls "arcus visionis, " which is not a given orb like in later astrology, but checking if the planet is really visible in the sky.

So many of his Medieval and Renaissance commentators give us lists of meaning for different positions of planets in respect of the Sun for different subjects like the quality of the soul, excess of passional soul and so on.

Margherita

Planets' phases are very important especially in Ptolemy, who judges about everything considering what he calls "arcus visionis, " which is not a given orb like in later astrology, but checking if the planet is really visible in the sky.

While it is true Ptolemy tried to precisely measure the heliacal phase of the planets Rumen Kolev doesn?t seem to think his calculations in the Almagest were very accurate:

From the Greeks, Ptolemy tried to compute the phases with a very simple and very inexact algorithm (of arcus visionis) described in the last chapter of the Almagest. The Arabs made their 'zij' tables of visibilities of the planets employing this for 1,000 years ! It gives very inexact results

.

According to Kolev the other Hellenistic authors didn?t even try to calculate the heliacal phase and simply used generalized ?orbs? based on the ecliptic positions rather than the location of the observer

The Greek astrologers simplified things further, accepting some limit of nearness to the Sun when they find a planet to be 'under the beams'. They measured this on the ecliptic of course. Dorotheus put different 'orbs of being under the beams' for different planets.
For Mars he gave 18 degrees and for Mercury 19.
Porphyry said that for a planet to have (any) power its distance from the Sun should be more than 15 degrees...Doing this though, the Greeks were well aware that this was a rough estimate. They (Valens, Porphyry, Rhetorius) explicitly talked about the heliacal phases and named them with their proper terms. 'Phasis anatolh -h' was used to denote heliacal rising and 'phasis dytikh -h' for heliacal setting.

He suggests the Arab and medieval astrologers had an even poorer understanding simply focusing on standardized ?orbs for ?under the beams?:

The Arabs moved further away from the real sky above Babylonia and Greece. They seemed, if not to have forgotten the phases, at least to pass them in silence. But they still talked a lot about a planet being 'under the beams'. Abenragel gave different orbs not only to the different planets but also as dependent on whether the planet was emerging from the Sun (heliacally rising) in the morning or was disappearing into the Sun ( heliacally setting) in the evening. For Mars he gave the values of 9 (rising) and 15 (setting) degrees distance from the Sun on the ecliptic and for Mercury he gave 7 degrees both ways. In later times Argolus gave 17 degrees to all planets as an orb for being under the beams of the Sun and that's it. Then, just few decades ago, most astrologers have not even heard about this!

Rumen Kolev suggests the correct understanding of this astrological technique of heliacal phase was developed by the Babylonians but largely lost in the hellenistic and medieval astrology.

The Babylonians could compute the heliacal phases of the planets based on their records of previous appearances and knowledge of the heliacal cycles.

I find it exciting that Rumen Kolev is researching the possibility of an astrological programme that will calculate planetary phase based on the observers location. He suggests all of the astronomical programmes that propose to do this at present fail.

Whatever, one?s view of Kolev?s understanding of traditional sources there is no denying he is one of the most gifted mathematicians working in astrology today. His contribution to a modern understanding of primary directions has been immense.

The development of a visual astrology programme able to accurately calculate planetary phase would do for the planets what Bernadette Brady?s Starlight has done for fixed stars.

MarkC wrote: While it is true Ptolemy tried to precisely measure the heliacal phase of the planets Rumen Kolev doesn?t seem to think his calculations in the Almagest were very accurate:

I don't know. Surely now we can measure it in more precise way.
But this is not important. When we should check if a planet is visible we tend to use a modern software, not Almagest.

The point is that Ptolemy would consider if a planet was free from the Sun, or retrograde or whatever with an astronomical observation, even if wrong. He did not use planetary orbs.

According to Kolev the other Hellenistic authors didn?t even try to calculate the heliacal phase and simply used generalized ?orbs? based on the ecliptic positions rather than the location of the observer

I agree.

I find it exciting that Rumen Kolev is researching the possibility of an astrological programme that will calculate planetary phase based on the observers location. He suggests all of the astronomical programmes that propose to do this at present fail.

I don't think it's very difficult. Myself I have a lot of formulas (but no intention to use them) but inside CieloeTerra they use them. Once upon a time, in DOS times, they had a software (impossible to run under XP, it crashes every 20 seconds) which graphically showed positions of planets in their epycles.
If they did in DOS.....

The development of a visual astrology programme able to accurately calculate planetary phase would do for the planets what Bernadette Brady?s Starlight has done for fixed stars.

You know quite well, I never saw anything of Brady's knowledge in any old text.
Paranatellonta are very different from Brady's paran, they share just the name.

Margherita

I don't know. Surely now we can measure it in more precise way.
But this is not important. When we should check if a planet is visible we tend to use a modern software, not Almagest.

Hi Margherita,

Fair point. I was just relating Kolev's point. Please take up any arguments with him!

The point is that Ptolemy would consider if a planet was free from the Sun, or retrograde or whatever with an astronomical observation, even if wrong. He did not use planetary orbs.

Absolutely I totally agree. The in mundo approach to heliacal phase is therefore a tecnique proposed by Ptolemy irrespective of the correctness his mathematical method.

I don't think it's very difficult. Myself I have a lot of formulas (but no intention to use them) but inside CieloeTerra they use them. Once upon a time, in DOS times, they had a software (impossible to run under XP, it crashes every 20 seconds) which graphically showed positions of planets in their epycles. If they did in DOS.....

I dont know if you are right here. I am neither a mathematician or astronomer so I am do not feel competent to agree or disagree. Hopefully some other members of the forum can pick this point up. It seems odd though that a mathematician like Kolev would make the claim that all current calculation programmes fail to properly identify heliacal phase by location without some good foundation. Do you think he is just trying to promote his update to the Placidus programme?

Looking at his posts the key difference between what he is factoring in and other programmes is what he refers to ''atmospheric quality'.
Rumen Kolev states:

The quality of the atmosphere on a given place is usually stable in the course of the years as to allow that stars and planets brighter than +1 magnitude to be seen with the same parameters. I have observed this many times. So, the planets being generally brighter than +1, they appear and disappear regularly having the same parameters and the babylonians could compute this.

The extinction (thickness) of the atmosphere can be measured very easily and it stays almost the same over the years. It has some cycle of change but it is not much. If you compute the thickness of the atmosphere at a given place now, the chances are that it has been the same or very close to that value 15 or 30 years ago.

My algorithm takes in account of course the thickness (the extinction) of the atmosphere. I hope to put it in this coming version 6.0 of my program Placidus so that at last I can look at a chart and see immediately wheteher a planet is visible or not. The algorithm of Schoch does not take in account the atmospheric extinction!
It is valid very roughly and only for very transparent atmosphere with extinction of around 0.12. But Schoch does not take in account also the magnitude of the planets! All assyriologysts for the last hundred years computed with his algorithm! I wonder how could they sleep at night!

I never saw anything of Brady's knowledge in any old text.
Paranatellonta are very different from Brady's paran, they share just the name.

Well that is a little hard. However, you are basically right that while Brady's astronomy is top notch her knowledge of traditional sources for meanings of fixed stars is not especially impressive. However, her software Starlight does allow easy calculation of in mundo stars rising or on the angles. I agree she rather misuses the word paran with Paranatellonta but that is another discussion!

Clearly there was software was around to do this before Brady produced her Starlight programme. However, she has popularised so called 'visual astrology' in an unprecedented way and given many astrologers a much better appreciation of what is in the real sky vs the hypothetical squeezing of the sky into the band of the ecliptic. I think she does deserve credit for that.

Rumen Kolev suggests the Ptolemaic or visual approach to heliacal phase was not entirely lost to medieval astrology. In particular he mentions the 16th century astrologer/mathematician Naibod:

In his book 'Enarratio Elementorum Astrologiae....", published in 1560, Naibod discusses the concept 'combustus' and writes that a planet is combust during the whole time of its invisibility. He critisizes the 'predominant' view of his time to procalim a planet 'under the beams' if it is less than a cetain fixed number of degrees distant from the Sun.
He then gives tables, much like those of Ptolemy, to compute the days of emergence (heliacal rising) and setting of the planets.

Mark

hi

I don?t think my "solution" helps with the other problems that you two are talking about but....

to the ones who want to calculate easily if a star is really on its heliacal rising (meaning - that got out of combustion or not)

if you have Janus, you can go to Map>sky and choose a time when the sun is 10 degrees in altitude below the horizon (or simply wait to the program tell you that there is daylight). Then you can see if the planet is visible or not.

It is not a sophisticated solution, but to the ones who don?t like orbs, but are not willing to buy software or to make the calculation by hand, it seem like a possibility :-)

Hello again Mark

MarkC wrote: Fair point. I was just relating Kolev's point. Please take up any arguments with him!

But I hate quarrel with whoever! It's just I have not the nuance of English, I just try to make intelligible my words, so maybe I'm little short with them, without any ribbon. But with a good heart

Absolutely I totally agree. The in mundo approach to heliacal phase is therefore a tecnique proposed by Ptolemy irrespective of the correctness his mathematical method.

What does it mean in mundo? I believe he just proposed to see at the real sky. Am I wrong?

I dont know if you are right here. I am neither a mathematician or astronomer so I am do not feel competent to agree or disagree.

Me neither.

Hopefully some other members of the forum can pick this point up. It seems odd though that a mathematician like Kolev would make the claim that all current calculation programmes fail to properly identify heliacal phase by location without some good foundation. Do you think he is just trying to promote his update to the Placidus programme?

Absolutely not. I just believe he has no idea what they do in CieloeTerra. In fact they don't sell their software, they use just inside their organisation as everything they elaborate.

It is valid very roughly and only for very transparent atmosphere with extinction of around 0.12. But Schoch does not take in account also the magnitude of the planets! All assyriologysts for the last hundred years computed with his algorithm! I wonder how could they sleep at night!

No idea who is this Schoch, I admit.
Anyway which difference can be? Somebody knows? I have not idea: minutes, days, weeks?
In every case for example a planet like Jupiter or Saturn is in its heliacal rising some days before and some days later, so if whatever software is wrong for two hours who cares?
It depends how much is the mistake margin. If it's a couple of hours I prefer the freeware!

However, her software Starlight does allow easy calculation of in mundo stars rising or on the angles. I agree she rather misuses the word paran with Paranatellonta but that is another discussion!

You can see which star is rising or culminating with whatever astronomical software.

In his book 'Enarratio Elementorum Astrologiae....", published in 1560, Naibod discusses the concept 'combustus' and writes that a planet is combust during the whole time of its invisibility. He critisizes the 'predominant' view of his time to procalim a planet 'under the beams' if it is less than a cetain fixed number of degrees distant from the Sun.
He then gives tables, much like those of Ptolemy, to compute the days of emergence (heliacal rising) and setting of the planets.

In fact Ptolemy commentators followed Ptolemy

Love,

Margherita

What does it mean in mundo? I believe he just proposed to see at the real sky. Am I wrong?

Thats is what I meant. In other words the actual position of a planet in the sky relative to the position of an observer on earth. This contrasts to the celestial position of a planet simply projected on to the ecliptic. The later is identical across earth in terms of ecliptical degrees while the former varies depending the precise location of the observer. However, the word 'visual' referring to the local sky is equally good and clearer.

MarkC wrote:However, the word 'visual' referring to the local sky is equally good and clearer.

I was sure we were talking about the same thing
Margherita

Hi Margherita,

I have a question which I would like clarification on regarding planetary phase using Ptolemy's visual approach.

I am wondering how heliacal phase ties into natal charts at night? Clearly at night nothing can be seen. How do we assess a planet in a natal chart in terms of heliacal phase on that basis? Lets assume a planet has already heliacally set and not yet risen in daylight in the local sky. Would I be correct in assuming this planet would still be interpreted as under the beams even if it might have separated many degrees from the Sun? Only if the planet had heliacally risen (or not set yet) would it be regarded as being free from beams? I am assuming this is the case. It would be similar to the Babylonian and Egyptian approach to fixed stars like Sirius which were regarded as lying in the underworld (Duat) before their heliacal rising occured.

Mark

MarkC wrote:
I am wondering how heliacal phase ties into natal charts at night? Clearly at night nothing can be seen.

I never heard about this for outer planets- maybe others know.

For example Jupiter in its heliacal rising is in phase both for night and day charts. Moreover I was taught this phase lasts some days so it's not very important to know the exact moment.
Still for a night chart Jupiter is against its hairesis. It can't work as it could work in a day chart.

On the other hand for inner planets, vespertine planets agree with night charts while matutine ones with daily chart.

In short words, in my opinion, you should combine the phase with the hairesis, i.e. as you call in English, the sect.

Margherita