1. The Celestial Sphere

2. The Caracol at Chichen Itza
Built around 1000AD.
The Mayans developed a very accurate calendar.
They also placed special significance on Venus.
Human Sacrifices were routinely performed to worship Venus

3. Name that constellation

4. Orion the Hunter

8. North Pole
Equator
The Celestial Sphere
South Pole

9. North Pole
Equator
South Pole

10. North Pole
Meridian
Equator
South Pole

11. North Pole
Meridian
Equator
South Pole

12. Celestial Sphere North Celestial Pole Celestial Equator
South Celestial Pole
North Celestial Pole
Celestial
Sphere
Celestial
Equator

13. NCP
Celestial
Meridian
Declination
CEq
SCP

15. Local Sky
Zenith N W E S
Horizon

16. NCP
Visible Half
of the Sky
Below the
Horizon N S Z E W
CEq
SCP

17. Measuring Latitude
Zenith
NCP
CEq N W E S
Latitude
Horizon

18. N S W E Z
NCP
Equator Z
NCP
North Pole Z
NCP N S W E
40º N Latitude

19. Evidence of Earth’s Rotation
Apparent Rotation of the Celestial Sphere
Star Trails
Cycle of Night and Day
Inertial Effects of Stuff on Earth
Coriolis Effect
Focault Pendulum
Precession of the Equinox

20. Apparent Rotation
of the
Celestial Sphere

21. Apparent Rotation
of the
Celestial Sphere

23. CEq NCP N Zenith Above Horizon for 12h Never Sets W S Never Rises E

27. The Coriolis Effect

28. Coriolis Effect

29. Differential Rotational Speeds
Arctic Circle
66.5º N: 666 km/h
Binghamton, NY
42º N: 1200 km/h
Equator
1670 km/h

30. Precession of the Equinoxes

31. Cepheus
Draco
Polaris
Ursa Minor
2000 AD
Thuban
2700 BC

32. Precession of the Equinoxes

33. Precession of the Equinoxes

34. Evidence of Earth’s Revolution
Sidereal Day vs. Solar Day
Seasons
Due to Earth’s tilt in combination with its Revolution about the Sun
Constellations and the Zodiak
As Earth revolves, different stars are visible at night

35. Solar & Sidereal Days T=24h (Solar day) T=23h 56m 04s (Sidereal Day)
Sun overhead
Noon
T=23h 56m 04s
(Sidereal Day)
One Earth rotation
T=0h
Noon
Not to Scale

37. Seasons
September
June
December
March

38. Seasons

39. Obliquity of the Ecliptic

40. 4 Seasons Autumnal Summer Winter Vernal Solstice Equinox NCP CEq
4th
1st
2nd
3rd
4 Seasons
Winter
Solstice
Summer
Vernal
Equinox
Autumnal
CEq
Ecliptic
SCP

41. NCP
Seasons
Ecliptic
CEq
~23.5º
Obliquity of
the Ecliptic
SCP

42. NCP
Seasons
Summer
Solstice
Ecliptic
CEq
Winter
Solstice
SCP

43. Seasons Autumnal Summer Equinox Solstice Winter Vernal Solstice
NCP
Seasons
Autumnal
Equinox
Summer
Solstice
Ecliptic
CEq
Winter
Solstice
Vernal
Equinox
SCP

44. Seasons Z Summer Solstice NCP Vernal & Autumnal Equinoxes W
CEq W
Winter Solstice S N E

45. Seasons CEq Z Summer Solstice NCP Vernal & Autumnal Equinoxes W
Winter Solstice S N E
Seasons
CEq

47. Angle and Intensity of Insolation

48. 1 KW/m2
1 KW/m2
1 m2
2 m2

49. Equinoxes: March 20 & Sept. 22
Spring and Fall

50. December 21: Winter Solstice
Northern Winter
Southern Summer

51. June 21: Summer Solstice
Northern Summer
Southern Winter

52. 2000 Dec 21: Winter Solstice
2001 Mar 20: Vernal Equinox
Winter
Spring
Summer
Autumn
2001 June 21: Summer Solstice
2001 Sept 22: Autumnal Equinox
Summer
Autumn
Winter
Spring

55. Constellations provide evidence that Earth Revolves around the Sun