I’ll be grading each question on a point scale. There are three grading categories: Completion (C): Full points will be given if you answered the full question, full points will not be given if you skipped any part of the question (so don’t skip anything!) Accuracy (A): These points are given based on if you got the question right or wrong. Partial accuracy points will be given for partially correct answers. Thoughtfulness (T): Any question that asks you to “explain”, “describe”, or answer “why?” should have more than a one-word answer. Any question that has T points should have answers that contain full sentences. Extra Credit: This will be graded on the C A T scale, the exam itself contains 10 total extra credit points. For one additional extra credit point, circle your signature at the bottom of this page and congratulate yourself for reading carefully.
- 1. The diameter of the Earth is about 1.3×107 m, the diameter of grapefruit is about 13 cm
(10 points: 5C 3A 2T)
- If we were to scale the Earth down to the size of a grapefruit, what would the scale factor be? (i.e. how many times smaller is the grapefruit compared to the Earth?) Show all work.(Hint: convert m to cm first)
1m = 100cm
1.3 x107 m=?
(1.3 x107) x 100 = 1,300,000,000 cm
1,300,000,000/13 = 100,000,000
The grapefruit is 100,000,000 times smaller compared to the Earth
- The radius of the Moon is about 3.5×106 m if we were to shrink the Moon down with the scale factor above, what size would it be in centimeters? What item could you compare this size to? Show all work.
1 m = 100cm
3.5×106 m =?
3.5×106 x 100 =350,000,000 cm
350,000,000/100,000,000= 3.5 cm
Comparing this size to the diameter of a pencil.
- The diameter of Jupiter (the largest planet in our solar system) is about 1.4x109m, if we were to shrink Jupiter with our scale factor, what size would it be in meters? What item could you compare this size to? Show all work.
1m = 100cm
1.4×109 m =?
1.4×109 x 100 = 140,000,000,000 cm
140,000,000,000/100,000,000 =1400cm
100cm = 1m
1400cm=?
1400/100 = 14 m
Comparing this size to the diameter of a swimming pool
- Starting with the new Moon, name all phases in order, sketch them, and give approximaterise and set times. Your options for rise and set times are “about” “12pm/3pm/6pm/9pm/12am/3am/6am/9am”. (i.e. you may only select “about 12am”, “about 3pm” etc.) In your sketch, the lit up portion of the Moon should be white. (10 points: 5C 5A)
Phase Name
Sketch
Approx. Rise Time
Approx. Set Time
New Moon
6 am
6 pm
Waxing crescent
12 pm
12 am
First-quarter
12 pm
12 am
Waxing
Gibbous
12 pm
12 am
Full moon
6 pm
6 am
Waning gibbous
6 pm
12 am
Last Quarter
12 am
12 pm
Waning crescent
12 am
12 pm
- If the Moon is currently in a waxing crescent phase, what phase will it be in 14 days? How do you
know this? (5 points: 2C 2A 1T)
First-quarter
This is because the moon takes 14 days to now get into a position where its 180 degrees from the sun, at this point a line can be seen and clearly defined first quarter is seen
- Use Stellarium, set your location to San Francisco, and turn on constellations. Set the date to December 5, 2020, and the time to 1:00 am. (10 Points: 3C 3A 4T)
- a) Find the star, Sirius. What constellation is it in? What are its azimuth and altitude? If you click on it you’ll see a link to it’s Wikipedia page, go there and read through the introduction section. Give me one interesting fact about Sirius.
The brightest star is seen from any part of earth , the star Sirius. It belongs to the Canis Major constellation. It is mostly referred to as the Dog star
- b) M31 is the most distant object we can see with the unaided eye. What constellation is it in? What are its azimuth and altitude? What type of object is it? Go to the Wikipedia page and give me one interesting fact about M31.
M31 is located in the constellation Andromeda, it is best observed in November
Its altitude and azimuth is 54⁰ / 072⁰
It is a giant elliptical galaxy
- (5 Points:2C 2A 1T)
- a) If you are in San Francisco, at which altitude and direction should you look to see Polaris? Explain your reasoning. (You may choose to draw a picture instead of a written explanation)
The polaris will be located high in the sky from a grounds point of view
- b) If you see Polaris at an altitude of 60o, what can you conclude about your location on Earth? Explain your reasoning. (You may choose to draw a picture instead of a written explanation)
if the polaris is at an altitude 60o then it means that youre east or west of the north pole
of the earth.
- c) Extra Credit:If you don’t see Polaris at all, what can you conclude about your location on Earth? Explain. (2 Points: 1A 1T) (You may choose to draw a picture instead of a written explanation)
If the polaris is not visible at all then it means that youre in the north pole. The north star doesn’t necessarily located in the north pole.
- What are the differences between the RA/Dec and Alt/Az coordinate systems? Why do we have
both? (i.e. what are the benefits of each?) (5 Points: 2C 2A 1T)
Alt/Az is the altitude and azimuth cordinate that changes from moment to moment from west to east whereas RA/Dec is cordinates based on the equitorial position of a body
The Alt/Az cordinates show how high from the horizon a star really is.
The RA/Dec shows where exact positions of each celestrial object are
- Use your star wheel for the following, all questions assume you are observing from San Francisco. one word answers are acceptable: (5 Points: 2C 3A)
- a) Which constellation is at zenith at midnight on July 24?
Apus
- b) Where in the sky should I look to find the constellation Auriga at midnight on December 12?
South to overhaed
- c) At what time on April 1 have all of the stars in Cassiopeia set?
At nightfall
- (10 points: 5C 3A 2T)
- a) You learned in Lab 7 that your Zodiac sign may not be what you originally thought it was. What determines our Zodiac sign and why does the Zodiac change over time?
The zodiac sign was originally derived from the constellation the sun was on the day of your birth however various factors have caused changes in the constellation we see in modern days
- b) What is your Birthday? What is your “new” Zodiac sign? What will it be in 26,000 years? Explain. (Hint:Look at page 1 of Lab 7)
Use October 9, 1999
the new zodiac sign is Saggitarius
The zodiac sign will be aquarius
This is due to the change in location of the sun in the constellation
- List the direction for sunrise and sunset for the Summer Solstice, Autumnal Equinox, Winter Solstice, and Vernal Equinox. You may choose from: N , NE, E, SE, S, SW, W, NW. Assume you are observing from San Francisco.
(5 Points: 1C 4A)
Summer Sol.
Autumnal Eq.
Winter Sol.
Spring Eq.
Rise Direction
North east
East
South
East
Set Direction
North west
West
South west
West
- One word answers are acceptable for partsa, b, c. (10 Points: 4C 4A 2T)
- a) During which season is the Sun highest in the sky?
Summer
- b) During which season is the Sun up in the sky for the longest amount of time?
Summer
- c) Which season is the warmest?
Summer
- d) Describe the two main reasons why the tilt of the Earth creates the seasons.
This is because the rotates around its own axis, therefore some places get sunshine throughout as the position is constant, when the earth tilts then there’s changes in seasons
- a) What is the objective lens of a telescope? Do we want large objective lenses or small objective lenses? Why? (5 Points: 2C 2A 1T)
This is the lens that focuses the image
The larger the objective lens then the more light it will collect.
- b) Extra Credit:When astronomers look through telescopes with their eye, they usually start with a less curved eyepiece. Once they’ve found what they’re looking for they might switch over to a more curved eyepiece. Why would they do this? (2 Points: 2A)
This is because the first curved lens focuses the image
while the second one is used for fine tune and sharpen the object
- Why is spectroscopy so important for astronomy? (i.e. What does spectroscopy tell us?)
(5 Points: 2C 2A 1T)
- Is the Universe static or not static? What evidence do astronomers have to prove this? Explain.
(Hint: You should reference Hubble’s Law in your answer). (5 Points: 2C 2A 1T)
Hubble discovered that the world was expanding over the years, this statement got criticism from some of the high profile scientist such as Albert Einstein. This means that it is a static universe
- Answer one of the following prompts in three or more sentences: (10 Points:6C 4T)
- b) What were a few things that you learned that were completely new to you?
The dog star is the brightest star seen on the earth’s surface.the north pole is 90 degrees while located. The sun is responsible for zodiac signs.
- Extra Credit:Answer a second prompt from Question 14: (2 Points:1C 1T)
- c) How have your opinions on astronomy changed over the past semester?
Astronomy is not very common to everyone, only the ones who get to study or have funds, yet over the past semester I have learned to grow interest in astronomy and figured out its quite an interesting topic