1. Charles Hakes Fort Lewis College1

2. Charles Hakes Fort Lewis College2 Introduction The Celestial Sphere

3. Charles Hakes Fort Lewis College3 Outline Lab notes Review Observing the Sun Unit Conversions RA/Dec SETI

4. Charles Hakes Fort Lewis College4 Notes Homework 1 due on Friday. Sun lab(s) due in “box”: Noontime Sun by next Friday 5:00 Sunset part1 by next Friday 5:00 Lab Resources Part B next week. Binocular lab next Mon,Thur (?)

5. Charles Hakes Fort Lewis College5 Observing the Sun http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/safety2.html http://www.mreclipse.com/Special/filters.html

6. Charles Hakes Fort Lewis College6 Measuring Angles A fist at arms length is about 10° Fingers spread wide are about 15° Three fingers together are about 5° One pinky width is about 1° The full moon is almost exactly 0.5°

7. Charles Hakes Fort Lewis College7 Dimensional Analysis Dimensional Analysis is VERY helpful in problem solving. Check your equations with specific units. Velocity example - how do distance (x), time (t), and Velocity (V) relate? V = x/t

8. Charles Hakes Fort Lewis College8 Dimensional Analysis Example - Which equation is correct? A) velocity = distance * time B) time = velocity * distance C) time = distance / velocity D) time = velocity / distance

9. Charles Hakes Fort Lewis College9 Which equation is correct? A) velocity = distance * time B) time = velocity * distance C) time = distance / velocity D) time = velocity / distance

10. Charles Hakes Fort Lewis College10 Velocity Exercise The laser travels 9.6m across the room. How many seconds does it take?

11. Charles Hakes Fort Lewis College11 Light Travel Time Across the Room (9.6 meters) A) 2.9x10 6 sec B) 2.9x10 -6 sec C) 3.2x10 -5 sec D) 3.2x10 -8 sec

12. Charles Hakes Fort Lewis College12 Light Travel Time Across the Room (9.6 meters) A) 2.9x10 6 sec B) 2.9x10 -6 sec C) 3.2x10 -5 sec D) 3.2x10 -8 sec

13. Charles Hakes Fort Lewis College13 Conversion Factors Conversion factors are equivalence statements expressed in the form of ratios Example: 1 in = 2.54 cm Conversion factors let you express a quantity in terms of other units without changing its physical value.

14. Charles Hakes Fort Lewis College14 Conversion Exercise Convert 0.61 m to inches.

15. Charles Hakes Fort Lewis College15 How many inches is 0.61m? A) 0.24 inches B) 1.56 inches C) 24.0 inches D) 156 inches

16. Charles Hakes Fort Lewis College16 How many inches is 0.61m? A) 0.24 inches B) 1.56 inches C) 24.0 inches D) 156 inches

17. Charles Hakes Fort Lewis College17 How many light years was that 9.6 m? A) 9.1x10 12 ly B) 1.0x10 -15 ly C) 2.9x10 9 ly D) 1.1x10 -14 ly

18. Charles Hakes Fort Lewis College18 How many light years was that 9.6 m? A) 9.1x10 12 ly B) 1.0x10 -15 ly C) 2.9x10 9 ly D) 1.1x10 -14 ly

19. Charles Hakes Fort Lewis College19 Significant Figures Example 4.56 has three significant figures. 4.56x10 6 also has three significant figures..000456 also has three significant figures. A calculation output can not have more significant figures than the input. If an equation has a whole number (for example 2) it is considered to be 2.00000 etc. Calculation hint - it is often best to keep all available figures until the last step, and then round your answer.

20. Charles Hakes Fort Lewis College20 Scientific Notation What does 1.0x10 6 mean? Positive exponents mean shift the decimal place to the right (bigger numbers). Negative exponents mean shift the decimal place to the left (smaller numbers). Usually only have one digit to the left of the decimal. Most calculators have a single key to add the (x10^) term. (EXP, EE)

21. Charles Hakes Fort Lewis College21 Measurements MultiplePrefix 10 9 giga- 10 6 mega- 10 3 kilo- 10 -2 centi- 10 -3 milli- 10 -6 micro- 10 -9 nano-

22. Charles Hakes Fort Lewis College22 Algebra Hint The following relationship will be useful to remember:

23. Charles Hakes Fort Lewis College23 Introduction The Celestial Sphere

24. Charles Hakes Fort Lewis College24 Oslo, Norway is 60°N latitude. What declination line passes through the zenith in Oslo? A) 0° B) 30° N C) 60° N D) 90° N

25. Charles Hakes Fort Lewis College25 Oslo, Norway is 60°N latitude. What declination line passes through the zenith in Oslo? A) 0° B) 30° N C) 60° N D) 90° N

26. Charles Hakes Fort Lewis College26 Astronomy Picture of the Day http://antwrp.gsfc.nasa.gov/apod/ap080922.html

27. Charles Hakes Fort Lewis College27 The Celestial Sphere Locations to note North celestial pole Celestial equator Declination corresponds to latitude. Right ascension corresponds to longitude. RA and Dec are “fixed” onto the celestial sphere.

28. Charles Hakes Fort Lewis College28 Figure P.4 Right Ascension and Declination

29. Charles Hakes Fort Lewis College29 Declination Declination corresponds to latitude. Units are degrees (and minutes and seconds). Durango’s latitude is +37.275° N. The declination line passing directly overhead is also +37.275° N.

30. Charles Hakes Fort Lewis College30 Oslo, Norway is 60°N latitude. How high does the star Polaris appear? A) 0° B) 30° N C) 60° N D) 90° N

31. Charles Hakes Fort Lewis College31 Oslo, Norway is 60°N latitude. How high does the star Polaris appear? A) 0° B) 30° N C) 60° N D) 90° N

32. Charles Hakes Fort Lewis College32 What is the southernmost declination line visible from Oslo (at 60° N)? A) 60° N B) 30° N C) 0° D) 30° S

33. Charles Hakes Fort Lewis College33 What is the southernmost declination line visible from Oslo (at 60° N)? A) 60° N B) 30° N C) 0° D) 30° S

34. Charles Hakes Fort Lewis College34 Standing on the equator, you can see… A) the celestial equator directly overhead B) entire celestial sphere during a 24 hour day C) both celestial poles on your horizon D) all of the above

35. Charles Hakes Fort Lewis College35 Standing on the equator, you can see… A) the celestial equator directly overhead B) entire celestial sphere during a 24 hour day C) both celestial poles on your horizon D) all of the above

36. Charles Hakes Fort Lewis College36 Durango’s latitude is 37.275° N. What is the southernmost declination line visible? A) 0° B) 37.275° S C) 52.725° S

37. Charles Hakes Fort Lewis College37 Durango’s latitude is 37.275° N. What is the southernmost declination line visible? A) 0° B) 37.275° S C) 52.725° S

38. Charles Hakes Fort Lewis College38 Right Ascension Right Ascension corresponds to longitude. Units are Hours (and minutes and seconds). The trick (as with longitude) is to decide on the zero point. Longitude zero is at the observatory in Greenwich England. RA zero is where the sun crosses the celestial equator going north. RA is always moving w.r.t. longitude.

39. Charles Hakes Fort Lewis College39 PRS question How long is the following exposure?

40. Charles Hakes Fort Lewis College40 Figure P.3 The Northern Sky

41. Charles Hakes Fort Lewis College41 How long is the exposure? Enter the correct number of hours. A) 4 B) 5 C) 6 D) 7 E) 8

42. Charles Hakes Fort Lewis College42 Three Minute Paper Write 1-3 sentences. What was the most important thing you learned today? What questions do you still have about today’s topics?