Lab2_Coordinates_Seasons

NAAP – Basic Coordinates & Motions 1/8 Name: Zachary Ziebold Lab 2: Basic Coordinates & Seasons – Worksheet There are three main sections to this module: terrestrial coordinates, celestial equatorial coordinates, and understanding how the ecliptic is related to seasons on the Earth. Each of these sections has its own simulator(s). The background material necessary to utilize these tools is contained in each section. Enter your answers to each question in the data tables and yellow highlighted areas below. When completed, please save and upload this file to the assignment submission link in Canvas. Terrestrial Coordinates Work through the explanatory material on units of longitude and latitude , finding longitude and latitude , and a bit of history (optional).  Open the flat map explorer .  Familiarize yourself with the cursor and how it prints out the longitude and latitude of the active map location.  Note that you can vary the central meridian of the map (i.e. change its longitude). Use the “shift map” arrows at the top of the simulator to affect large rapid changes. Use the shift-click feature of the cursor for finer control.  Note what information is accessible through the show cities and show map features check boxes.  Center the cursor on your present location. Click the open Google Maps button to launch the Google Map tool focused on this location. Experiment until you get a good feeling for the Google Map’s capabilities and then close this window. (Note that you must be connected to the Internet to make use of this feature.) Question 1: Use the flat map explorer to complete the following table. You are encouraged to try and predict the answers and then use the map’s cursor and other features to check the accuracy of your estimates. Location Longitude Latitude The center of the island of Madagascar. 46.4 º E 19.5 º S Honolulu, Hawaii, United States 157.5º W 21.2º N London, England Prime Meridian 51.8º N Havana, Cuba 82.1º W Tropic of Cancer Sao Paulo, Brazil 46.8 º W 23.7 º S

NAAP – Basic Coordinates & Motions 2/8 Chukchi Sea, Russia International Date Line Arctic Circle New Orleans, Louisiana, United States 90º W Meridian 30º N Parallel Question 2: Determine which of the 50 states defines the farthest extent of the United States in each of the 4 map directions. Direction State North Alaska South Hawaii East (there are two ways of thinking about this) Maine or Alaska West Alaska Question 3: The exact coordinates of the white house in Washington D.C., are 77.0365º W and 38.897º N. What are these exact coordinates in sexagesimal notation? Show your calculation below. (You can use the Google Map tool to check your answer.) 77 º .0365 * 60 = 2.19’ .19 * 60 = 11.4’’ 77 º 2’ 11.4’’ W 38 º .897 * 60 = 53.82’ .82 * 60 = 49.2’’ 38 º 53’ 49.2’’ N 77 º 2’ 11.4’’W and 38 º 53’ 49.2’’ N  Open the globe explorer. You are encouraged to use the Terrestrial Coordinate Explorers link which opens both simulators at the same time for the following two questions. Familiarize yourself with the features noting that they are very similar to those in the flat map explorer. Question 4: A) Where is the north pole on the flat map explorer ? What is its shape? 90.0 º N and 0 º W, there is no shape, only blank space is displayed.

Question 5: Compare the relative sizes of Greenland and Australia in the two maps? The true values of the surface areas for these countries are Greenland (2.2 million km 2 ) and Australia (7.7 million km 2 ). Does each map demonstrate these true values? Greenland appears to be significantly larger on a flat map because of the distortion near the poles of the map. Australia on the other hand would appear to be larger on the globe due to its location and distortion on a flat map. Celestial Equatorial Coordinates Work through the introductory material on the page entitled Celestial Equator, Declination, Right Ascension .  Open either the Flat Sky Map Explorer or the Sky Map Explorer .  Familiarize yourself with the same set of features (cursor movement, shifting the map, decimal/sexagesimal) that were available on the previous maps.  Make sure that you understand what each check box does. Question 6: Where is the star Polaris located on this map? What are its coordinates? Polaris is located near the top of the map at the center, the coordinates of Polaris are Delta = 89.2º, Alpha = 2.5h. Question 7: Find the constellation of Orion shown in the box below and measure the right ascension and declination of its brightest stars Betelgeuse and Rigel. Note that Orion is located on the celestial equator. RA 5.9h DEC 24.4 º RA 5.2h DEC -8.2 º

Question 8: Which direction is east on the flat sky map? Relate this to a coordinate of the celestial equatorial system. On the sky map east appears to be to the left, and the coordinate of the celestial equatorial system is 0 to 12H. Question 9: Complete the following table of positions on the ecliptic. Ecliptic Location Approximate Date Right Ascension Declination Vernal Equinox March 21 0H 0 º Summer Solstice June 21 6H 23.5 º Autumnal Equinox September 21 12H 0 º Winter Solstice December 21 18H -23.5 º Question 10: Write out a description of the ecliptic on the flat sky map. What does the shape look like? Describe the ecliptic in terms of its average and range of declination values. The equinoxes are located where the celestial equator and the ecliptic intersect, while the solstices are located at the crests and valleys of the ecliptic line. The celestial equator is a straight line horizontal across the flat sky map while ecliptic looks like a trigonometric equation, waving up and down, above and below the origin or celestial equator. The ecliptic reaches its maximum when the summer solstice occurs and the minimum when the winter solstice occurs. Seasons and the Ecliptic Work through the introductory material on the page entitled Orbits and Light .  Open the Seasons and Ecliptic Simulator .  Note that there are three main panels (left, upper right, and lower right) each of which have two different views. Controls run along the bottom of the simulation that affect more than one panel. Click animate and then move through the six views to get an overview this simulator’s capabilities. We will address each of these six views separately.  Experiment with the various methods to advance time in the simulator. You may click the start animate/stop animation button, drag the yearly time slider, or drag either the sun or the earth in the left panel to advance time.  Note that this animation does not illustrate the rotation of the earth. Because the timescales of rotation and revolution are so different, it isn’t possible to effectively show both simultaneously.

Upper Right Panel – View from Side  This view shows the earth as seen from a location in the plane of the ecliptic along a line tangent to the Earth’s orbit. It allows one to easily see the regions of the Earth that are in daylight and those that are in shadow.  Dragging the stick figure allows one to very conveniently change latitude. Dragging the stick figure on top of the subsolar point effectively puts the observer at the latitude where the direct rays of the sun are hitting.  Although rotation is suppressed in this simulation, keep in mind that the stick figure is on a planet that is rotating with a period of 24 hours about an axis connecting the north and south poles. Thus, 12 hours later it will be on the other side of the earth.  Set up the simulator for the image at right – the winter solstice for an observer at 80  N. Since this observer’s parallel of latitude is located entirely in the shaded region, this observer will not see the sun on this day. Lower Right Panel – Sunbeam Spread  This view shows a “cylinder” of light coming from the sun. It is projected on a grid to convey the area over which the light is spread. As this light is spread over a larger area, its intensity decreases. Lower Right Panel – Sunlight Angle  This view shows the angle with which rays of sunlight are striking the Earth. It lists the noon sun’s angle with respect to the horizon (its altitude).  Verify that when the noon observer is at the latitude where the most direct rays of the sun are hitting, the sun is directly overhead making an angle of 90  with the ground.  Verify that when the noon observer is at the latitude where the least direct rays of the sun are hitting, the sun is on the horizon. Tip: Once the stick figure is selected you can gain greater precision over its motion by moving the mouse a distance away from the figure.

Question 11: The table below contains entries for the coordinates for the sun on the ecliptic as well as the latitude at which the most direct and least direct rays of the sun are hitting. Use the simulation to complete the table. May 5 has been completed for you. Date RA DEC Latitude of Most Direct Ray Latitude of Least Direct Ray February 5 2.3 h -15.8 º 15 º S 75.0 º N March 21 23.9 h 0 º 0 º N 90 º N May 5 2.9 h +16.5° 16.5° N 73.5° S June 21 6.1 h 23.4 º 23.5 º N 66 º S August 5 9.2 h 16.3 º 17.2 º N 73.5 º S September 21 12.1 h -.6 º 0 º N 90 º N November 5 14.9 h -16.6 º 14.2 º S 73.5 º N December 21 18.1 h -23.4 º 22 º S 66 º N Question 12: Using the data in the table above, formulate general rules relating the declination of the sun to the latitude where the most direct and least direct rays of the sun are hitting. Firstly, during the winter, the southern hemisphere receives the most direct rays of sunlight. On the other hand, during the summer, the northern hemisphere receives the most direct rays of sunlight. The latitude of most direct rays of sunlight is either equal to or approximately equal to the declination. Question 13: The region between the Tropic of Cancer and the Tropic of Capricorn is commonly known as the tropics. Using the sunlight data table from question 11, define the significance of this region. Each of the tropics are located at 23.5 º and the area in-between is referred to as the tropics. This area commonly receives the most direct sunlight on Earth and therefore tends to maintain considerably warm climates. Question 14: Using the sunlight data table from question 11, define the significance of the region north of the Arctic Circle commonly referred to simply as the Arctic. Due to the tilt of the Earth, the poles at certain times of the year will either receive days of constant sunlight or no sunlight.