Skyscript Astrology Forum

In India, even today, there are various panchanga (ephemeris) floating around with planets in different degrees. Is it possible that something like this could have happened in 762 AD with the Astrologer picking an ephemeris that fitted his idealized election chart.

I agree

Lastly, is it true that Caliph al-Munsur had the Indian astronomical text Surya Siddhanta translated into Arabic around 760 ADbecause they were getting pre-occupied by predicting the time of crescent moon.

That is interesting. If you have a source for the comment I'd love some details.

Some years ago, I recall making my own conversion of Al Biruni's 23 Tammuz, Alexandri 1024, and noting that it did correspond to 30 July 762 JC as Pingree reported. But is is some years ago and now I don't remember how I did it. I looked on the internet a few weeks ago to try to find a source of conversion, but those I found don't go this many years back. I agree with Juan that its a redundant point once the details of the chart can be confirmed; however, it is relevant if there is a need to judge between arguments of corresponding positions on 30th or 31st, according to different zodiacs.

Thanks for filling me in on the convention of historians to default to JC Juan - still I see no reason for astrologers to do that when passing on data for modern recalculation.

In the year 156 of the Hijra (a.d. 773), there
appeared before the Caliph Al Mansur a man who had come
from India ; he was skilled in the calculus of the stars known as
the Sindhind (i.e. Siddhanta), and possessed methods for solving
equations founded on the kardagas (i.e. kramajya, sines) calcu-
lated for every half degree, also methods for computing eclipses

http://archive.org/stream/AHistoryOfAst ... r_djvu.txt

In Sunset to sunset scheme: 30 July equivalent should span from: say 30 July 6PM to 31July 5.59PM

PD

Deb wrote:I agree with Juan that its a redundant point once the details of the chart can be confirmed; however, it is relevant if there is a need to judge between arguments of corresponding positions on 30th or 31st, according to different zodiacs.

Since the differences between zodiacs in this case are less than half the daily motion of the Moon, the actual modern date is obtained from the approximate lunar position regardless of the zodiac used. The chart that appears on page 263 of the Sachau edition of Biruni shows the Sun in 8,10 Leo around the 9th or 8th houses, which places the time near 2 p.m., and the position of the Moon given as 19,10 Libra is possible only on July 30th (julian).

Juan

the position of the Moon given as 19,10 Libra is possible only on July 30th (julian).

Using Krishmanurti + 3.53 the Moon is at 19.10 Libra around 4:15 am 31 July JC. The inability to replicate the Moon's position more exactly is annoying, but I don't believe it is possible to get the Moon near to that degree, (by any zodiac) whilst keeping the ascendant near Sagittarius and the Sun around the 9th or 8th houses. If it were, then I would favour the chart that allowed that to happen. We have to decide whether the arguments for the Sagittarius ascendant are strong enough to admit the error is with the Moon's position, and I think they are since they come from multiple sources. Juan, if you are able to get the Moon at 19.10 Libra without losing the Sagittarius ascendant and the quadrant placement of the Sun, please provide the data as I'd be very interested - this is something I have spent some time checking already.

I just noticed your earlier post PD - thanks for that.

Deb wrote:Juan, if you are able to get the Moon at 19.10 Libra without losing the Sagittarius ascendant and the quadrant placement of the Sun, please provide the data as I'd be very interested - this is something I have spent some time checking already.

In previous emails I had not made the actual chart, but now I have it in front of me on the screen and I see your point.

Just for the record, let me say that I am not expecting the lunar position to be exact, I am assuming that it will be approximate within plus or minus 5 or 6 degrees, which is a common error I have seen when comparing ancient charts with modern computation.

I am also checking as I write the text by Ibrahim Allawi. As you have mentioned he provides a copy of the original manuscript with the horoscope drawn with arabic letters and numerals (fig.5), and later on in Table 1 he provides the positions according to this chart. It is here where some discrepancies or errors are evident, that I was not aware of when I wrote my first comments based on him back in 2003, and that you have brought to my attention now.

Allawi gives the lunar position from Biruni as 29,10 Libra. This is the position I used originally, that supports the July 31st date. But in my previous post I ignored this and mentioned instead the lunar position given by Sachau which I had at hand, and this position is 19,10 Libra, which changes the situation and makes the July 30th date plaussible. Since I had based myself on Allawi before, I had not considered this date.

Since you have provided the positions as listed by David Pingree giving the Moon in 19 Libra, it becomes evident as you are pointing out that Allawi made a mistake.

Another discrepancy from Allawi is to list Saturn in 1,40 Aries with an error of 0,15 from the tropical position, which makes it evident that the position should be read as 1 Taurus. The confusion augments with the fact that Sachau's translated version of the horoscope on page 263 does not include Saturn (that I can see), while Pingree says it is given by Biruni as 26,40 Aries. This Saturn position by Pingree contradicts the 2 independent positions listed by Allawi in Table 1 from Biruni and Ibn al-Faqih, which however he lists as 1 Aries but calculates the modern tropical offset from 1 Taurus.

So I understand now --and was not aware before-- the ambivalence of the 2 dates (July 30 and 31st).

In my limited experience the position of the Sun in ancient horoscopes tends to be exact withing about half a degree, contrary to what is the rule in the case of the Moon. If we assume that 1) the degree of the Sun is correct and 2) the zodiac used was that of the Zij-Al-Sha, using Riyal I get

2:30 pm apparent time

July 30 762
Sun 7,04 Leo / Moon 11,10 Libra

July 31 762
Sun 8,01 Leo / Moon 24,55 Libra

Juan

In my limited experience the position of the Sun in ancient horoscopes tends to be exact withing about half a degree, contrary to what is the rule in the case of the Moon. If we assume that 1) the degree of the Sun is correct and 2) the zodiac used was that of the Zij-Al-Sha, using Riyal I get

2:30 pm apparent time

July 30 762
Sun 7,04 Leo / Moon 11,10 Libra

July 31 762
Sun 8,01 Leo / Moon 24,55 Libra

We get a little closer to the reported positions using Krishnamurti+3.53.
At 2:44pm LMT, 30 July 762 JC:
Sun: 7.10 Leo / Moon 11.22 Libra
Difference from reported postion: Sun: -1d 0m / Moon: -7d 48m

By comparison (2:40pm on 31 July 762 JC):
Sun: 8.02 Leo / Moon 25.04 Libra
Difference from reported postion: Sun: -0d 2m / Moon: +5d 54m

After originally favouring the 30 July date, I then rejected this because of the larger computational difference for the Sun and Moon - though I have noted that the difference decreases for the rest of the planets, all of which seem to be over-calculated according to modern computation.

I've recently been reading some of Kennedy's Survey of Islamic Astronomical Tables - a good amount is available on Google preview. One point Kennedy makes clear is that there were masses of alternate tables around at this time - most with Persian or Indian influence. He notes that the accuracy of the tables increases during Al Mansur's reign. At this point in time, the tables were likely to have some inaccuracies, but I think we should give more weight to the position of the Sun and Moon, than the relatively minor improvement we get for the rest of the planets by using the 30th rather than the 31st.

Juan, I mentioned earlier my own confusion over the Saturn position. But if you check the image of the Arabic chart in Allawi's paper (p. 63), you'll see that there should be a planet in Aries, where Sachau's chart is blank. So I assume that Pingree reported what he could read in that original image. I imagine that the degree of Jupiter was also given in that chart, but the detail was too indistinct to be read with any confidence.

I wish there was a way to verify Allawi's report of al-Faqih's positions. I've tried to find a copy of the text myself, but without success.