2. Our Location on the Earth

3. North South EastWest

4. North South East you are here West

5. Our Location on the Earth North South EastWest

6. North South EastWest Earth’s direction of rotation

7. Our Location on the Earth North South EastWest

8. North South EastWest Equator

9. North South EastWest Equator Prime Meridian

10. Our Location on the Earth North South EastWest Equator Prime Meridian

11. Our Location on the Earth North South EastWest Equator Prime Meridian

12. Our Location on the Earth North South EastWest Equator Prime Meridian longitude

13. Our Location on the Earth North South EastWest Equator Prime Meridian longitude latitude

14. Our Location on the Earth North 122 o 23’ west longitude 47 o 57’ north latitude MTHS, WA

15. Our Location on the Earth North Brier, WA The Earth turns to the east

16. Our Location on the Earth North Brier, WA

17. Our Location on the Earth North Brier, WA

18. Our Location on the Earth North Brier, WA

19. Our Location on the Earth Brier, WA North

20. Dome of the Sky North Horizon Zenith Nadir meridoan Simulation

21. Dome of the Sky North Horizon looking south looking north Zenith Nadir toward north star

22. Dome of the Sky south north zenith toward North Star

23. Dome of the Sky north zenith toward pole star south

24. Dome of the Sky

26. Zenith North Meridian Horizon

27. Zenith North Meridian Azimuth Altitude East Horizon

28. Zenith North Meridian Azimuth Altitude

29. ZenithNorth Meridian Azimuth Altitude

30. Celestial Sphere

33. North Celestial Pole (NCP)

34. Celestial Sphere North Celestial Pole (NCP)

35. Celestial Sphere North Celestial Pole (NCP) Celestial Equator

36. Celestial Sphere Celestial Equator North Celestial Pole (NCP)

37. Right Ascension (RA) Declination (Dec) Celestial Equator Celestial Sphere

38. NCP Right Ascension (RA) Declination (Dec) Celestial Equator Celestial Sphere

39. Right Ascension (RA) Declination (Dec) Celestial Sphere

40. Right Ascension (RA) Declination (Dec) One of the two points on the Celestial Sphere where the Ecliptic and the Celestial Equator cross one another, The First Point of Aries, which is actually in Pisces, defines the zero-point for Right Ascension. When the Sun reaches the First Point of Aries, as it does once each year, an equinox occurs. In the northern hemisphere, this is the Vernal Equinox, the first day of Spring.

41. The First Point of Aries is not a fixed point in space: it moves along the Ecliptic at a rate of roughly one degree every seventy years. When the Equinox was first observed, thousands of years ago, the First Point actually lay in the constellation of Aries. Due to the effect of precession, the First Point of Aries crossed into the neighboring constellation of Pisces in about 70 BCE. It has taken about 2,000 years to cross Pisces, and it will soon cross into the next zodiacal constellation, Aquarius, in about the year 2600. Following its journey along the Ecliptic, it will return to its starting point in Aries once again in about 23,000 years.

42. The Sky from Here From the ground, the sky looks like a big dome above us. Both the “zenith” and horizon are locally defined.

43. Celestial Equator and Pole We project the Earth into the sky, and its rotation appears reflected there. The “diurnal” (daily) motion of the sky is just due to the spinning Earth.

44. Celestial Coordinates To “map” a given point in the sky, you can specify how high it is, and in what direction (altitude and azimuth). Or you can project latitude (declination) and longitude into the sky, but since the Earth rotates, we must use “right ascension” which is fixed on the stars.

45. Let’s set it all in motion Diurnal Motion - –The rotation of the Earth –This causes the stars to change during a night –They rise in the East and set in the West –Or rise in the SE and set in the SW

46. Motion of the Stars Do all locations on Earth see the same motion of the stars? Visible Sky Simulation

47. Motion of stars as seen from Brier

49. Let’s set it all in motion Night sky changing through the year –Earth’s orbit around the Sun –Stars up at sunset change during the year Zodiac Simulation

50. Let’s set it all in motion

51. Usefulness of the Constellations We can use the constellations to orient ourselves in the sky Polaris - The north star –in Brier our latitude is 48 degrees north –Therefore Polaris is 48 degrees above the horizon –This means you can always know your latitude in the northern hemisphere by knowing were Polaris is Let’s look to the Northern Sky

52. Northern Sky

53. Usefulness of the Constellations The constellations can also tell you the time of year by looking to the east around the time of Sunset. Let’s look at the what you might see in the Summer or Winter

54. Winter Triangle

55. Summer Triangle

57. Chart of the Sky Note how the Sun appears to go North and South as the year progresses. The zero point of Right Ascension occurs at the Spring crossing of the Equator (vernal equinox). The solstices occur at the maximum N/S excursions.