1. The Night Sky What are constellations?
Why do we see some in winter, some in summer and some all year long?
Why do they move?
How are they useful?

2. The most simplest observation in Astronomy: Look at the night sky
About 3000 stars visible at any one time; distributed randomly but human brain tends to find patterns…
These patterns are constellations

3. Group stars into constellations: figures having meaning to those doing the grouping
Useful: Polaris, which is almost due north
Served as markers
Daily and yearly rhythms

4. The Night Sky Motion of stars caused by Earth’s rotation
As Earth spins, we are carried beneath the sky so that the stars move from east to west

5. VLT
Night Sky Time lapse

6. The Night Sky
Watch the sky over a year, notice each season has its own constellations
Orion- January
Leo- March
Scorpios- June
Tells Time of Year

8. Astrology NOT Astronomy
Pseudo-science which claims that the positions of the heavenly bodies have an effect on the lives of human beings and events on Earth.

9. Why do we see some constellations in winter, some in summer and some all year long?
Results from our planet’s orbital motion around the Sun
Different parts of sky become visible
Sun’s glare

10. Why do the Stars Move?
There are five constellations that we consider as being circumpolar. We have seperated them into two groups.
Group 1: Ursa Major, Ursa Minor, Draco
Group 2: Cassiopeia, Cepheus

12. Why do the Stars Move?
The Stars don’t actually move… It is the Earth that is moving (spinning).
The spinning Earth gives the perception that the stars move.
Polaris – Earth’s northern axis points at this star so its movement is not affected by Earth’s Rotation.

13. How are Constellations Useful?
Finding N, S, E & West
Find Big Dipper… then follow end stars over to Polaris (the North Star)
Track your position on Earth (navigation)
What about the 5 wanderers?

14. The 5 Wanderers
5 Planets
Four of which are easily visible without a telescope.
They are Mercury, Venus, Mars, Jupiter, and Saturn.
Mercury is more difficult to see due to its proximity to the Sun.

16. The Night Sky

17. Because of orbital motion of the planets around the sun, planets move across the sky at different speeds than stars
Always rise in east and set in the west, orbital motion of the planets usually shift eastward in respect to the stars
Watch the night sky, focus on a planet and a star near it in the sky, planet moves slightly slower

18. Planet may shift westward through the constellations
Caused by Earth’s motion
Over a couple of nights
Car moving backward as pass

19. Eclipse Lunar Eclipse Solar Eclipse Earth’s shadow strikes the moon
only at full moon
Solar Eclipse
Moon’s shadow strikes the Earth

20. Eclipse Next Lunar Eclipse: Oct 18, 2013
Next Solar Eclipse: Nov 3, 2013

22. What is an eclipse?
Blockage of light from astronomical body caused by the passage of another body between it and the observer

23. Zodiac
A band running across the celestial sphere in which the planets move

24. Apparent Motion vs. Retrograde Motion
Apparent Motion: movement of any body in space actually caused by Earth’s revolution or rotation
Retrograde Motion: movement in which a planet moves forward, then backward, then forward again as observed from Earth