1. How could you describe to someone where a location is on Earth?
Bellwork 9/19
How could you describe to someone where a location is on Earth?

2. Coming Up
Today: Begin Constellations and Positions, Finish modeling lab if needed
Friday 9/21: Finish Planisphere practice, Celestial Sphere computer simulation
Tuesday 9/25: Stellar Parallax notes & activity
Thursday 9/27: Review
Tuesday10/2: Begin Unit 2
Thursday 10/4: Unit 1 Test

3. A few things… Content Rubric Lab Rubric Scientific Reasoning Rubric
Be prepared for a Lunar Phase/Eclipse lab question on your test!!!

4. Earth-Moon system Moon Phases
The relative positions of the Sun, Earth, and Moon constantly change
Lunar phases are a consequence of the motion of the Moon and the sunlight that is reflected from its surface
It’s because of our perspective from Earth…what we can see at any given time…
This is NOT Earth’s shadow!

6. Lunar motions Moon's period of rotation about its axis and its revolution around Earth are the same
Causes the same lunar hemisphere to always face Earth
Synodic month
Cycle of the moon phases
Takes 29 1/2 days

7. “To obscure light from”
Eclipses
“To obscure light from”
Solar eclipse
Moon moves in a line directly between Earth and the Sun
Can only occur during the new-Moon phase
Lunar eclipse
Moon moves within the shadow of Earth
Only occurs during the full-Moon phase
**For any eclipse to take place, the Moon must be in the plane of the ecliptic at the time of new- or full-Moon **

8. Solar eclipse

9. Lunar eclipse

10. Moon Motions The Moon DOES rotate on its axis
The Moon revolves at the same rate it rotates
The Moon takes about 28 days to revolve around Earth…not 24 hours...
The Moon rises & sets, just like the Sun and constellations

11. Understanding the Celestial Sphere

12. How could you describe to someone where a location is on Earth?

13. Pareidolia--the tendency to perceive a specific, often meaningful, image in a random or ambiguous visual pattern

14. People of the past used this phenomenon to designate locations & positions in the night sky.
Why would they care to do that?

15. Constellations A recognizable pattern of stars in the sky
Used to separate & locate regions of the sky
88 constellations
They were not all designated at one time

16. Constellations Bayer System System of labeling stars
First for Brightness
Using Greek alphabet
α Brightest
β 2nd Brightest
And so on

17. Celestial Sphere
Stars appeared to move around a fixed point and rotate around Earth
We now know that these “star trails” are due to the Earth’s rotation…not the stars’.

19. Celestial Meridian:
Divides the sky in half from north to south.
Zenith:
Bisects the meridian
This point never changes on the celestial sphere, but from the observers’ point of view, the stars at the zenith change
“Actual” zenith vs. “local” zenith
How do we tell “what’s what”?

20. Locating Objects in the Sky: There are 2 ways to look at it…
1. Equatorial system of location
Two location components
Declination – the angular distance north or south of the celestial equator
Measured in degrees 
Right ascension – the angular distance measured eastward along the celestial equator from the position of the vernal equinox
Measured in hours & minutes 

21. Right Ascension (or "RA") and Declination (or "Dec") are global coordinates
any particular star has the same RA and Dec for all observers on Earth, and that position remains the same, night after night.

22. Locating objects in the night sky: Local Coordinates
2. Altitude and Azimuth
local coordinates
each observer sets up his own reference frame
Altitude and Azimuth of a given star will change over just a few minutes as the star appears to move across the sky

23. Ecliptic Zodiac The apparent path of the sun through the stars
The broad belt of constellations that lie along the ecliptic
12 total constellations

24. Anatomy of a Planisphere:
Inner ring: time of day
Declination: Degrees in “viewing window”
Middle ring: Months & Days
Outer ring: Right ascension (hours & minutes)

25. How to use a Planisphere
IF NEEDED, set the planisphere to the correct day and time
Make sure you’re holding the planisphere in the correct orientation
 “East horizon” on the right, “West horizon” on the left
Find the Declination
Find the Right Ascension (a straight edge can be helpful with this)

26. What the heck am I looking at?!?
Horizon (looking South)
Horizon (looking North)
Directly overhead…or the Zenith

27. Planisphere Practice:
What is the RA & Dec. of Arcturus? (near constellation Bootes)
RA: ~14hr 15min
Dec: ~+20⁰

28. Planisphere Practice:
What is the RA & Dec. of Betelgeuse? (in constellation Orion)
RA: ~6hrs
Dec: ~+8⁰

29. Planisphere Practice:
Set your planisphere to September 16th at 10:00pm. Name a constellation that is RISING (on the East Horizon).
Taurus
Perseus
Aries
Ect…

30. Planisphere Practice:
Set your planisphere to January 12th at 6:00pm. Name a constellation that is SETTING (on the West Horizon).
Sagitta
Cygnus
Capricornus
Ect…

31. Planisphere Practice:
Set your planisphere to February 28th at 8:00pm.
Name a constellation that is close to its ZENITH.
 Zenith = bisecting line of the meridian…
SO divide your “window” in half horizontally and choose a constellation at that bisecting line
Gemini, Auriga, Camelopardalis

32. Bellwork 9/22 What unit is Declination measured in?
What unit is Right Ascension measured in?
What is the purpose of measuring Declination & Right Ascension?

33. Reminder: Today: Finish up constellations & positions
Tuesday 9/26: Stellar Parallax & Review
Thursday 9/28: Unit 1 Test

34. Bellwork 9/21
How do astronomers communicate the location of objects in the celestial sphere? …There is more than one answer here!

35. Coming Up—B Day
Today: Begin Constellations and Positions, Finish modeling lab if needed
Friday 9/21: Finish Planisphere practice, Celestial Sphere computer simulation
Tuesday 9/25: Stellar Parallax notes & activity
Thursday 9/27: Review
Tuesday10/2: Begin Unit 2
Thursday 10/4: Unit 1 Test

36. Coming Up—A Day
Today 9/20: Finish Planisphere practice, Celestial Sphere computer simulation
Monday 9/24: Stellar Parallax notes & activity
Wednesday 9/26: Review
Monday 10/1: Begin Unit 2
Wednesday 10/3: Unit 1 Test

37. Anatomy of a Planisphere:
Inner ring: time of day
Declination: Degrees in “viewing window”
Middle ring: Months & Days
Outer ring: Right ascension (hours & minutes)

38. What the heck am I looking at?!?
Horizon (looking South)
Horizon (looking North)
Directly overhead…or the Zenith

39. Planisphere Practice:
What is the RA & Dec. of Pollux? (within the constellation GEMINI)
RA: ~7hr 45min
Dec: ~+28⁰

40. Planisphere Practice:
What is the RA & Dec. of Sirius? (within the constellation CANIS MAJOR)
RA: ~6hr 45min
Dec: ~-17⁰

41. Planisphere Practice:
What is the RA & Dec. of Vega? (within the constellation LYRA)
RA: ~6hr 45min
Dec: ~-17⁰

42. Planisphere Practice:
Set your planisphere to October 15th at midnight.
Name a constellation that is close to its ZENITH.
 Zenith = bisecting line of the meridian…
SO divide your “window” in half horizontally and choose a constellation at that bisecting line
Cassiopeia, Perseus

43. Planisphere Practice:
Set your planisphere to March 20th at midnight.
Name a constellation that is close to its ZENITH.
 Zenith = bisecting line of the meridian…
SO divide your “window” in half horizontally and choose a constellation at that bisecting line
Ursa major

44. Planisphere Practice:
Set your planisphere to February 28th at 8:00pm.
Name a constellation that is close to its ZENITH.
 Zenith = bisecting line of the meridian…
SO divide your “window” in half horizontally and choose a constellation at that bisecting line
Gemini, Auriga, Camelopardalis

45. Planisphere Practice:
Set your planisphere to September 16th at 10:00pm. Name a constellation that is RISING (on the East Horizon).
Taurus
Perseus
Aries
Ect…

46. Planisphere Practice:
Set your planisphere to January 12th at 6:00pm. Name a constellation that is SETTING (on the West Horizon).
Sagitta
Cygnus
Capricornus
Ect…

47. Planisphere Practice:
Set your planisphere to July 15th at 9:00pm. Name a constellation that is RISING (on the East Horizon).
Pegasus Delphinius
Aquarius
Capricornus

48. Planisphere Practice:
Set your planisphere to April 15th at 11:00pm. Name a constellation that is SETTING (on the West Horizon).
Gemini, Canis Minor, Cancer, Auriga