Digest Number 494

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In a message dated 3/13/2003 1:19:54 PM Central Standard Time,

sidereal writes:

 

> Fagan's work rested firmly on the scholarship of almost a

> hundred years when he realized in 1944 that the Babylonians had

> used a sidereal zodiac. It's one thing for a scholar to see it and

> something else again for a long-time tropicalist (as Fagan had been

> since 1916) to make the leap, because first he had to understand it.

>

 

Thanks, Ken, for your entire response in Digest Number 494. /// wing

 

 

 

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Thursday, March 13, 2003 1:08 AM

Digest Number 494

 

 

> " How can Pluto be in Sagittarius when it's so close to Antares? " -----

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>Message: 3

> Wed, 12 Mar 2003 15:02:22 -0000

> " Ed Kohout " <crumpo

>Re: sidereal reference frames - Ed.

>

>Hi Juan!

>

>Thanks for the fine info, and the insights. You are truly the Dean

>of Astronomy in our ranks. It shows that I read too many astrology

>books and not enough technical stuff.

>

>But, I still say that the " sidereal zodiac, " no matter what the

>Babylonians used, is now calculated as some delta from the vernal

>point, and thus defined as such, and not by reference to any fixed

>star near the ecliptic; nor is it somehow anchored on some fixed

>point in space.

 

 

Dear Ed,

I think your comments about proper motion are misleading. It

depends very much on which stars you're talking about. You

couldn't throw Bernard's freight train, for example, into the mix.

Let's look at Antares, one of the prime fiducial stars in the sidereal

zodiac, important to both the Babylonians and latter day

siderealists. It's apparent place on January 1, 1901 according to

the American Ephemeris and Nautical almanac was,

RA 16h 23m 20.1s

dec. -26 deg. 12' 38.8 "

when these values are converted to celestial latitude and longitude,

one gets a tropical longitude of 8 Sag. 22' 46.75 " and latitude

-4 deg. 33' 19.86 "

The sidereal longitude was 15 Scorpio 01' 02.85 " .

 

One hundred years later for January 1, 2001 the apparent place of

Antares according to the Astronomisches Rechen-Institut, an

internationally recognized authority was,

 

RA 16h 29m 25.73s

dec. -26 deg. 25' 54.29s

Converting these values to celestial longitude and latitude one gets

a tropical longitude fugure of 9 Sag 45' 59.71 " and latitude of

-4 deg. 34' 11.5 " . The sidereal longitude for this period was

15 Scorpio 01' 00.7 "

The difference in tropical longitude in 100 years for this star is

1 degree 23' 12.95 " or 4,992.95 seconds in 100 years.

 

The difference in sidereal longitude in 100 years is 2.15 seconds,

so yes, you're right, if you insist on splitting hairs, proper motion is

a factor but it will take several millennia for sufficient proper motion

to accrue such that the difference between now and then could

subtend an arc capable of being discerned by the human eye. So

as a practical matter the sidereal zodiac is a fixed frame of

reference. I'm therefore confounded as to why you would claim

that sidereal reckoning is secondary to tropical because in the

ancient world the equinox was described in terms of the sidereal

zodiac, not the other way around.

Fagan and Bradley were not looking to put Aldebaran at the

fiducial point. They found it there courtesy of Joseph Epping S.J.,

Johann Strassmaier S.J. and F. X. Kugler S.J. who spent much of

their adult lives deciphering Babylonian and Assyrian astronomical

texts, which were brought together and expanded by Otto

Neugebauer in his Astronomical Cuneiform Texts.

 

I'm further confounded as to why you would maintain that 1st

Nisan of April 3, 786 B.C. was invisible. The New Moon in right

ascension occurred at 8:50 PM LMT on the evening of April 2nd

and the New Moon in longitude more than an hour before that. So

if sunset was at about 6:10 PM on the evening of April 3rd at

Babylon and the Sun would have been sufficiently depressed below

the horizon about thrity to thirty five minutes later for the Moon to

be seen, that means the Moon was about 22 hours old and had

sufficient altitude to be seen. The youngest Moons are 14 hours

old and although a Moon that new is rare, a 22 hour Moon is not

rare. How then can you blithely dismiss this New Moon as

invisible? The only issue which could put the matter into doubt is

the modest difference in azimuth between this Sun and Moon but

the Moon's anomaly can easily take care of that issue.

Even though the earliest horoscope extant dates to 410 B.C.,

astronomical/astrological work does not appear ex nihilo. Abraham

Sachs, who along with Neugebauer was in perhaps the best

position to know, stated that while there is no evidence extant for

it, he assumed the tradition to be some centuries earlier than 410.

Just how far is difficult to say because the solid evidence for period

relations and the kinematic model that allows predictions of future

planet positions is a late development. But it is significant that one

can't solve the problem of period relations with a tropical system of

reference because era to era comparisons break down except with

sidereal reckoning. It is only by comparing sidereal and synodic

periods from one era to another that period relations can be derived.

You can't do that with tropical reckoning. Besides, nobody could

find the equinox in the ancient world anyway. All of Ptolemy's

measurements of it were wrong although he got some of them

tolerably close; and except for Callipus' lucky hit in 330 B.C. the

equinox was a very approximate thing, not remotely as definitive a

fiducial as a star all through early and late antiquity.

You state that the Babylonians could calculate the position of

the Moon acurately in 786 B.C. and yet you throw cold water on

the zodiac then. I don't maintain that it is so, although the

exaltation solution is suggestive, but it should be borne in mind

that the zodiac is a tool that facilitates positional computations.

That's how they did it. That's what the normal stars were for. The

12 fold equal division zodiac comes directly out of the normal star

schema. The question is when did they change from the 17

unequal constellations of circa 1100 B.C. (according to Francesca

Rochberg-Halton in her 'New Evidence for the History of the Zodiac'

[Journal of New Eastern Studies, 1984]) to the 12 fold equal

division format.

Fagan's work rested firmly on the scholarship of almost a

hundred years when he realized in 1944 that the Babylonians had

used a sidereal zodiac. It's one thing for a scholar to see it and

something else again for a long-time tropicalist (as Fagan had been

since 1916) to make the leap, because first he had to understand it.

 

Ken Bowser

Minneapolis, Minnesota