Charles Hakes Fort Lewis College1

Charles Hakes Fort Lewis College2 Introduction The Celestial Sphere

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

Charles Hakes Fort Lewis College4 Notes Homework 1 due on Wednesday. Remove “spiral fringe” from three minute papers In MasteringAstronomy, make sure your student ID is your FLC student ID! If you are still having login issues – drop by my office after class or during office hours.

Charles Hakes Fort Lewis College5 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.

Charles Hakes Fort Lewis College6 Conversion Exercise Convert 0.61 m to inches.

Charles Hakes Fort Lewis College7 How many inches is 0.61m? A) 0.24 inches B) 1.56 inches C) 24.0 inches D) 156 inches

Charles Hakes Fort Lewis College8 How many inches is 0.61m? A) 0.24 inches B) 1.56 inches C) 24.0 inches D) 156 inches

Charles Hakes Fort Lewis College9 Significant Figures Example 4.56 has three significant figures. 4.56x10 6 also has three significant figures 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 etc. Calculation hint - it is often best to keep all available figures until the last step, and then round your answer.

Charles Hakes Fort Lewis College10 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)

Charles Hakes Fort Lewis College11 Measurements MultiplePrefix 10 9 giga mega kilo centi milli micro nano-

Charles Hakes Fort Lewis College12 Algebra Hint The following relationship will be useful to remember:

Charles Hakes Fort Lewis College13 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

Charles Hakes Fort Lewis College14 Dimensional Analysis Example - Which equation is correct? A) velocity = distance * time B) time = velocity * distance C) time = distance / velocity D) time = velocity / distance

Charles Hakes Fort Lewis College15 Which equation is correct? A) velocity = distance * time B) time = velocity * distance C) time = distance / velocity D) time = velocity / distance

Charles Hakes Fort Lewis College16 Velocity Exercise The laser travels 9.6m across the room. How many seconds does it take?

Charles Hakes Fort Lewis College17 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

Charles Hakes Fort Lewis College18 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

Charles Hakes Fort Lewis College19 How many light years was that 9.6 m? A) 9.1x10 12 ly B) 1.0x ly C) 2.9x10 9 ly D) 1.1x ly

Charles Hakes Fort Lewis College20 How many light years was that 9.6 m? A) 9.1x10 12 ly B) 1.0x ly C) 2.9x10 9 ly D) 1.1x ly

Charles Hakes Fort Lewis College21 Observing the Sun

Charles Hakes Fort Lewis College22 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°

Charles Hakes Fort Lewis College23 How High is the Sun at noon? A) 90° B) >75° C) <75° D) cannot determine

Charles Hakes Fort Lewis College24 Introduction The Celestial Sphere

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

Charles Hakes Fort Lewis College26 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

Charles Hakes Fort Lewis College27 Astronomy Picture of the Day

Charles Hakes Fort Lewis College28 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.

Charles Hakes Fort Lewis College29 Figure P.4 Right Ascension and Declination

Charles Hakes Fort Lewis College30 Declination Declination corresponds to latitude. Units are degrees (and minutes and seconds). Durango’s latitude is ° N. The declination line passing directly overhead is also ° N.

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

Charles Hakes Fort Lewis College32 Oslo, Norway is 60°N latitude. How high does the star Polaris appear? A) 0° B) 30° N C) 60° N D) 90° N

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

Charles Hakes Fort Lewis College34 What is the southernmost declination line visible from Oslo (at 60° N)? A) 60° N B) 30° N C) 0° D) 30° S

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

Charles Hakes Fort Lewis College36 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

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

Charles Hakes Fort Lewis College38 Durango’s latitude is ° N. What is the southernmost declination line visible? A) 0° B) ° S C) ° S

Charles Hakes Fort Lewis College39 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.

Charles Hakes Fort Lewis College40 PRS question How long is the following exposure?

Charles Hakes Fort Lewis College41 Figure P.3 The Northern Sky

Charles Hakes Fort Lewis College42 How long is the exposure? Enter the correct number of hours. A) 4 B) 5 C) 6 D) 7 E) 8

Charles Hakes Fort Lewis College43 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?