http://online.chabotcollege.edu/shildreth/astronomy/bbsunsign.html

Chabot College - Scott Hildreth

Answers to HW#1: Where was the Sun when you were born?

Part A.  (Opinion) What do you think about Astrology?  Do you read your horoscope?  Do you *believe* it? :) 

Observation: Most people responding to this question over the many years it has been asked in our class share that they don't really believe in Astrology, but find it "fun".  Some go farther, and share that they see many "coincidences" in the description for people of particular sunsigns and the behavior of those people - including themselves.  A few responders every term say that they firmly believe in Astrology, of various kinds (there are many, including Vedic astrology, as well as "western", using tropical and sidereal zodiacs.)  They often say that sunsign astrology to them is not really important, and that true astrologers look more deeply at planets, positions, and aspects.  And many other people say that they ignore it altogether, finding it complete nonsense. 

In the past few years, the controversy about sunsigns reappeared when the media picked up upon the disparity between western astrological signs and where the sun actually was in front of the real stars.  You might enjoy reading:

            Anders, C. (2011) Why did your zodiac sign change?  Zodiac Apocalypse Debunked. IO9.com.Accessed 6/9/11 from http://io9.com/5733004/your-zodiac-sign-may-have-changed-this-week

Part B.  (Investigation) Where was the Sun (really!) when you were born?

5) Record your actual Sun sign.  Is it the same as the one you thought was "yours"? (To explain why your actual sign is probably NOT the same as your astrological sign, you will need to read more about precession.)

For most people, the predicted sunsign based on your birthdate will NOT line up with where the Sun actually was on your birthday.  Some folks born in front of large zodiacal signs, like Pisces and Virgo, may still see the sun in front of "their" astrological sunsign, but this is more an accidental result of the constellation being rather large. Folks born under the smaller signs of Aries or Cancer, for example, will typically NEVER find that the Sun actually was in front of those sign.

For more information about astrology, you might want to read:

    And you might enjoy seeing how the actual sun's position has shifted over the years because of precession, and the accompanying table of "dates" according to its author, Daniel Delaney. 

6) Do you think the results in the above activity depend on what time you were born? In other words, if you were born at night, would the position of the Sun be in front of a different background constellation than if you were born during the daytime? :

  No - What TIME of day you were born will not generally affects your sunsign!

 

        7) Most people do believe the results depended on what time you were born, but they do not. 

7a) How long does it takes for the Sun to appear to go around the entire ecliptic once (that is, in front of all twelve zodiac constellations)?

It takes the Sun around a month to move through the sky in front of an average-sized zodiac constellation. And it takes the Sun an entire YEAR to move through all twelve zodiac constellations!  That is, it takes a year for Earth to orbit the Sun once, and during that span of time, the Sun will slowly appear to move eastward in front of those twelve constellation.  If you could see the sun at noon every day, and have it magically be totally eclipsed for a minute, you would see the background stars of the zodiac constellation around the Sun. Every month, it would be a different constellation.

Note that this is NOT asking how long it takes the Sun to move across the sky during the day due to the Earth's rotation! In one rotation of Earth, th Sun *and* the background constellations will all move across the sky, rising in the East and setting in the west.  But during that day, the Sun will NOT move very far at all in front of the background.  This question is asking about the Sun's apparent motion because of the Earth's revolution!

7b) If you were born around the middle of the "window" of time for any particular zodiac sign (say around April 5 for an "Aries"), would the sign change if you were born a day earlier, or a day later?  So does the sun move much along the ecliptic in front of the same zodiac constellation in 24 hours?

Since the sunsign is the same for about 30 days in a row, it doesn't matter whether you were born a day earlier or later, unless you were born on the changing point between signs (called the "cusp").  If you were born on April 5, you would officially be an Aries astrologically.  One day earlier, you were still an Aries officially.  One day later, the same.  In reality, for all of those dates, the sun was in front of the constellation of
 Pisces!

7c) How far along the ecliptic will the Sun move in about 12 hours? (How many constellations will it pass through in just 12 hours? All twelve? Just six? Or not even one?)

If the Sun moves once around the ecliptic in a year (360 degrees), then it moves about 1 degree every day.  In half a day, the Sun will move about 1/2 of a degree, which is less than the distance across the sky of your little finger held at arm's length.  As it turns out, the Sun itself is about1/2 a degree in *angular size*, so that Sun moves about its own width in 12 hours in front of the background stars. We don't see this motion because the Sun is so bright we can't see those background stars until after the Sun sets, and by then, you can't easily see where the Sun was located! 

Because it takes the Sun an entire year to make it around the ecliptic (and through all twelve zodiac constellations), in one day it won't move very far at all.  So whether you were born at dawn, noon, sunset, or midnight, your sunsign will not vary much at all.

9) Can you see "your" zodiacal constellation sunsign in the sky at midnight on your birthday? Why or Why not?

No - your sunsign is the zodiac sign the Sun is in front of when you are born, and it won't change based on the clock time (which is set by the Earth's rotation, not by where we are around the Sun in our orbit.)  So if your sign was Aries, for example, then when the Sun rises, the constellation behind it is Aries, at noon the Sun is still in front of Aries, at sunset it is *still* in front of Aries, and at midnight the Sun - which you cannot see - would still be in front of Aries - which you can't see either!

9a) To answer this, set your Star Locator for midnight on your birthday, and record the three zodiac constellations visible near the meridian line (the line running directly North-South across the sky).9b) Are any of these your actual (or astrological) sun signs? Why not?

None of these will be your sunsigns - they will actually be the zodiac constellations exactly opposite of your sunsign.  So if you were born on April 1, and had an astrological sunsign of Aries, but a real sunsign of Pisces, on midnight in April you would see the constellations of Leo, Virgo, and Libra in your sky.

9c) Try setting your Star Locator for 6 PM on your birthday. Where (east, west, or overhead) is your sunsign?

            You would see your sunsign due west, right near the sun still!  If the sun is setting, so would the constellations behind the sun that entire day.

 6/09/11 - SH

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