Zodiac - intro

In a previous blog I mentioned the difference between ecliptic and equatorial coordinates. The plane of the ecliptic is important because nearly all of our solar system lies in the plane of the ecliptic.  Once interplanetary travel becomes commonplace we may abandon equatorial coordinates.  The word ecliptic is derived from the word eclipse, something that happens because the earth, moon and sun all lie in the same plane.

Today I want to teach you how to orient yourself with ecliptic coordinates.  The easiest way to do this is with the constellations of the zodiac.

The word zodiac comes from the latin word zodiacus which means circle of animals.  The signs of the zodiac do not line up with their constellations.  This is mostly due to precession.

The northern zodiac constellations are Virgo, Leo, Cancer, Gemini, Taurus, Aries and Pisces.  For me the easiest to find is Leo.  At its apex the lion lays flat on a plane elevated above the horizon in the southern sky.  The prominent sickle shape forms a mane and the bright star Regulus marks a front paw. Virgo is to the left of Leo and all the other constellations are to the right in the order above.

Zodiacal light is sunlight reflected off of interplanetary dust.  You will not see this if there is much light pollution.

If you want to spot planets I really think first you should know your zodiac.  Planets will always be in one of the zodiac constellations.

Unicode Symbols of the Zodiac

♈	Aries
♉	Taurus
♊	Gemini
♋	Cancer
♌	Leo
♍	Virgo
♎	Libra
♏	Scorpio
♐	Sagittarius
♑	Capricorn
♒	Aquarius
♓	Pisces