1. Celestial Sphere Facts: It’s an imaginary sphere with earth in the center. It is useful for locating constellations and stars on a star map

2. Zenith: Zenith is the point on the celestial sphere directly over the head at any point of time Nadir: Nadir is the point on the celestial sphere directly below the observer at any point of time. Celestial Meridian: The imaginary circle passing the North and South points on the horizon and through the zenith.

3. Celestial equator: Imaginary line on celestial sphere in the same plane as earth’s equator. Celestial poles: Celestial North pole and Celestial South pole are north and south points on the celestial sphere, when earth’s imaginary axis is extended all the way to touch the celestial sphere. Celestial Coordinates: Position of a star in the map Right ascension Equivalent to longitude on a map. Counted in hours (not in degrees as in longitude), along the equator. Declination Equivalent to latitude on a map. Counted in degrees, perpendicular to the equator.

4. Horizon: Line where the sky meets ground or sea Ecliptic: Path of the sun on the celestial sphere

5. Constellations – A constellation is a group of visible stars that form a pattern when viewed from Earth. The pattern they form may take the shape of an animal, or some mythological figure or some object. – Useful to identify the position of stars in the sky – There are 88 named constellations

6. Sky map – Shows location of constellations

7. Constellations have imaginary boundaries formed by "connecting the dots" and all the stars within those boundaries are labeled with the name of that constellation. The individual stars in a constellation may appear to be very close to each other, but in fact they can be separated by huge distances in space and have no real connection to each other at all. For example, look at the image below of the stars which make up the constellation Orion. The stars in this easily-observed constellation are at VERY different distances from Earth!

8. ConstellationSeasons visible (Northern hemisphere) Main Star BootesSpring - Summer Canis MajorWinter - Spring CassiopeiaAll year around CephusAll year around CygnusWinter – Spring – Summer DracoAll year around GeminiWinter – Spring LeoWinter – Spring - Summer

9. ConstellationSeasons visible (Northern hemisphere) Main Star OrionWinter - Spring ScorpiusSummer TaurusFall - Winter Ursa MajorAll year around Ursa MinorAll year around VirgoSpring - Summer