Sirius!

Over the past couple of weeks, I've been chipping away at an
article on Canis Major for Night Sky Magazine. Obviously, the
first thing one has to talk about is Sirius, and the primary
piece of lore about that star is that the ancient Egyptians
used its heliacal rising to predict the floods of the Nile.

For those who don't know, "heliacal rising" means the first
day in the year when a star is visible immediately before
sunrise. It was a critically important concept in Egyptian,
Babylonian, and Greek astronomy, and I've always wondered why.

Part of the reason, I realized recently, is astrology. It's
an unpallatable fact to most modern astronomers, but there's
very little doubt that astrology was the primary motivation
for the amazing theoretical and practical astronomy that was
done by the ancient Greeks. Mind you, astrology was controversial
even back then; there were plenty of people who scorned it.
But Ptolemy, the greatest ancient astronomer by far, was
not one of them. Indeed, the Tertabiblios, his work on
astrology, has sold far more copies than the Almagest.

In order to know what your "sign" is, you need to know where
the Sun was in relation to the fixed stars on your birthday.
That may sound simple, but understanding that there *are*
stars near the Sun during the daytime is a stretch that most
modern, presumably sophisticated people have never made.
And figuring out the Sun's exact position was a remarkable
technologic and intellectual feat, especially considering
that accurate clocks wouldn't be invented for another
couple of millenia. The key step, of course, is to note
which stars are visible at sunrise and sunset. Knowing
that, and knowing the star's positions, you can triangulate
in on the position of the Sun.

Anyway, on Monday or Tuesday, while I was contemplating
what to write about Canis Major, I woke up around 5:30
and looked out the window to see if I would have had
clear skies if I had stayed up late the night before.
And there, low in the east, in a bright blue sky, was
a lone, bright, twinkling light. I knew it couldn't be
Venus or Jupiter, because those are evening planets now.
Mars would have been much higher. That left only Sirius
as a possibility. And straining my eyes, I confirmed that
by observing Rigel and Betelgeuse to its upper right,
vastly fainter even though they were much higher, and
in a much darker part of the sky.

A thrill ran through me, seeing for the first time this
year the star that will be dominating the sky five or
six months from now. And for the first time, I really
understood at a gut level why the ancient astronomers
were so excited about the heliacal rising of Sirius.

- Tony Flanders

.

Relevant Pages

  • How to Get Started In Amateur Astronomy
    ... When you look up at the darkened sky and gaze at the stars, ... Read about astronomy. ... of observing the many wonders of the sky. ... Purchase a star atlas or a star map which will enable you to ...
    (sci.astro.amateur)
  • Re: How to Get Started In Amateur Astronomy
    ... When you look up at the darkened sky and gaze at the stars, ... Read about astronomy. ... of observing the many wonders of the sky. ... Purchase a star atlas or a star map which will enable you to ...
    (sci.astro.amateur)
  • Re: Newbie looking at buying a scope....
    ... just familiarize yourself with the night sky in general. ... in order to learn the constellations many people recommend an all ... paperback book called "Star Maps for Beginners" by I.M. Levitt and Roy ... The first and last parts of the book present general astronomy ...
    (sci.astro.amateur)
  • Re: Sirius!
    ... Obviously, the first thing one has to talk about is Sirius, and the primary piece of lore about that star is that the ancient Egyptians used its heliacal rising to predict the floods of the Nile. ... It was a critically important concept in Egyptian, Babylonian, and Greek astronomy, and I've always wondered why. ... And there, low in the east, in a bright blue sky, was ...
    (sci.astro.amateur)
  • Star of Bethlehem
    ... Re: Star of Bethlehem ... within the realm of ancient astrology. ... At the time of the birth of Christ astrology and astronomy were the ... The 'Star' was revealed in an ancient astrological chart by the ...
    (sci.astro)
Loading