The Celestial Sphere Lab Report

The Celestial Sphere Lab Report Date _09/20/2023_________________ Group Members Names Role Leader (manages people and time) l Recorder (completes and submits group report) Checker (makes sure all results are correctly reported) 1. Explain the following terms: a. Right ascension – is an angle measured counterclockwise on the celestial equator from the intersection point of the celestial equator and the ecliptic. It is also measured in hours. For ex. (360 degrees / 24 hours) = 15 degrees in one hour of right ascension. b. Declination – is defined as an angle that describes an object’s position north or south of the celestial equator c. Latitude – Latitude is the angular distance between the equator. The line of latitude is a circle line on the Earth's parallel equator. d. Longitude – Longitude is the distance between the prime meridian ( Greenwich ) and any location at earth’s surface. e. Altitude - Altitude (Alt) is the angular distance between the horizon and an object in the sky. It is measured in degrees and can vary between 0 degrees and 90 degrees. f. Azimuth – Azimuth (Az) is the angle measured from north toward east. Stars on the sphere are represented by small circles of various sizes. 2. What is the name of the brightest star in the constellation of Cygnus? Deneb 3. What is the name of the brightest star in the constellation of Lyra? Vega 4. Complete the table below. Star Name Constellation Name R.A. Dec. Arcturus Bootes 14h +19° Sirius Canis Major 6h -16 ° Altair Aquila 19h +8° Pollux Gemini 7h +28 ° Procyon Canis Major 7h + 5 ° Rigel Orion 5 h -8° 5. Set the Globe for Washington D.C. for today’s date at noon: a. Which constellation is closest to the zenith at noon? Leo Minor b. What is the Sun's altitude at noon? 90 degrees c. What direction would you face in order to see the Sun at noon? South d. Rotate the celestial sphere and Sun while holding the Earth knob still to find how many hours after noon sunset occurs. (Give your answer to the nearest ½ hour) 6 hours e. What is the Sun's altitude at sunset today? 0 degrees f. What direction would you face to watch the sunset today? West g. At what longitude is it noon when the sun is just setting in Washington, D.C.? 6. List two stars that are just rising at sunset today.

List two stars that are just rising at sunset today. Star name Constellation Right Ascension Declination Altitude Azimuth Capella Auriga 5h 16m 41s +45° 26.4 degrees 48.3 degrees Castor Gemini 07h 34m 36s +31° 55 degrees 7. Now rotate the sky to 3 hours past sunset and record the altitudes and azimuths of the stars Star name Constellation Right Ascension Declination Altitude Azimuth Epsilon Pegasi pegasus 21h 9 +16 Alpha Pegasi Pegasus 23h 15 +20 8. What constellation is closest to being at the zenith today at midnight? A. Reset the globe for Dec. 19 a. What is the sun’s altitude at noon now? 55 degrees b. How many hours before it sets? 5 hours c. Where should you look to see the sunset? West B. Reset the globe for June 14 a. What is the sun’s altitude at noon? 25 degrees b. How many hours before it sets? 9 hours c. Where should you look to see the sunset? West C. Describe differences you see in the sun’s altitude and path across the sky over the course of the year based on what you have learned from setting the globe for the solstices and an equinox. The sun's altitude increases later on in the year. D. Gently remove the globe from the “cradle” and set it so the North pole points directly at the zenith, simulating an observer at the north pole. a. Describe how stars move at the north pole : the stars begin to move in counterclockwise circles when you face upwards or horizontally to the right when you have the horizon. b. Reset the globe in its cradle to see the view of the sky as an observer at the equator would have. How do stars appear to move for this observer? The stars appear to revolve from east to west about the celestial poles on circular paths parallel to the celestial equator. c. How do stars appear to rise and set for our latitude? (estimate the angle above the horizon for this) : As the spin of the earth carries us eastwards, we see stars rising in the east passing overhead and setting in the west. 9. Application: All the planets, asteroids and comets move with respect to the background stars which are much farther from us than objects in the solar system. But some objects seem to change positions faster than others. a. List reasons you think some objects might appear to move more with respect to background stars than others. What are some of the factors that might be involved? The distance of the object relative to the viewer and it revolution around the sun