Hi guys, I’m a bit of a newbie to astronomy and I’m just trying to figure out
some fundamental basics.
I know that each sign of the zodiac occupies 30 degrees of the ecliptic and
this in turn equates to 2 hours of Right Ascension, all adding up to 360
degrees and 24 hours. All good so far.
So I start at the start: 0 hours Right Ascension, March 20th, exactly where
the sun crosses the line at dawn. The puzzling thing is, instead of being at
the start of Aries(given as March 21st – April 19th),the sun is rising in
front of Pisces and continues to do so until April 21st.
It seems that the dates officially given for each sign of the zodiac are ahead
of what is actually happening by a month.
Can someone please help explain why or point me in the right direction? I
would be very grateful.
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Astrology is a fraud, those dates in your daily horoscope haven't been valid
for 2000 years now
The tropical zodiac is made up of 12 signs - and _not _ the constellations. It
is a coordinate system that covers the entire sky with each sign extending
from the north ecliptic pole to the south ecliptic pole rather like slicing an
orange twelve-fold with signs sweeping out slices across the sky (like hours
of RA do) .
Thus the signs are celestial geometry and constellations are the stars
patterns from which the signs have adopted their names.
Since the signs and the RA system are anchored to the same equinox they are
subject to precession causing the signs to slip away from their original
constellation namesakes over the last 2000 years.
Like the RA system the signs begin at the equinox with sign Aries (not
constellation). All celestial objects in the sky therefore have a zodiacal
position in a sign with an accompanying zodiacal longitude and latitude. Thus
the star Alkaid in Ursa Major is currently in the sign Virgo at 27 degrees and
zodiacal latitude 55N.
Because the equinox is subject to precession both the RA system ad the
tropical zodiac system slip westward over time. so that the original
constellations from which the signs adopt their names have now some 30 degrees
I guess the million dollar question is - WHY hasn't this been adjusted in over
2000 years to match the current positions?
It's so much why was it not adjusted, it's that astrologers chose to use the
tropical zodiac rather than the constellations probably because the tropical
zodiac is synchronised with the seasons (anchored to the equinoxes and
solstices). It is of interest to note the likes of Copernicus, Galileo and
Kepler who were very well versed in celestial geometry also cast horoscopes in
the tropical zodiac. They would have been very well aware of precession
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