ACTIVITY 1 The Celestial Sphere and Sky Maps Introduction In this activity students learn more about the features of the sky where to look when to look how the sky changes and why it changes The Background section introduces the terms of the celestial sphere This information would serve as a good review for students if they already have familiarity with the related concepts from their reading and lectures This activity will then guide them through applying that knowledge to star maps We have found that many students do not know the difference between rotate and revolve This leads to confusion when we ask about daily changes in the sky due to Earth s rotation versus yearly changes due to Earth s orbit This activity introduces the fact that the motion of the stars around Polaris the star closest to the north celestial pole is due to Earth s rotation We also bring in the relationship between the altitude of Polaris and an observer s latitude The next topic is the change in the sky due to Earth s revolution around the Sun We introduce the zodiac and the motion of the Sun along the ecliptic Before covering this yearly motion ask students why the constellation Orion is viewable at night in the winter but not in the summer Alternatively bring in Harry Potter s impossible astronomy assignment of finding and charting Orion in June during his O W L exam The four star maps for the activity are located in the Appendix on pages A1 A4 They represent the night sky at approximately midnight on the equinoxes and solstices Question 20 in the Putting It Together section would be good as a post activity class discussion using think pair share groups or short writing exercise Students are asked to compare images of a Sun centered image with the views of the celestial sphere essentially Earth centered over a year The question is Was investigating the sky from these two points of view helpful or not Explain No additional materials are needed for this activity Learning Goals After completing this activity students will be able to 1 contrast daily and yearly motion of the stars 2 state the altitude of the north celestial pole Polaris from their locations 3 describe how stars move over the course of a year 4 5 6 evaluate the effectiveness of viewing the night sky from different reference frames identify constellations that lie on the meridian and the ecliptic identify the locations of the solstices and equinoxes on the celestial sphere Key Terms celestial sphere constellation ecliptic zodiac celestial equator equinox solstice zenith horizon meridian latitude north celestial pole NCP circumpolar rotate revolve Pre and Post Activity Questions Overview of Smartwork Questions and PowerPoint Slides Pre activity student actions include ranking locations on Earth based on altitude of Polaris deciding which celestial events are due to rotation or revolution of Earth labeling parts of the celestial sphere identifying when the Sun is at its highest at noon Post activity student actions include ranking of celestial occurrences sorting of constellations based on their location relative to the meridian labeling the position of the Sun on a star map over a period of months determining why constellations change positions throughout a year Workbook Activity Steps and Solutions Step 1 Background This activity starts with an emphasis on the vocabulary of the celestial sphere It relates the position of the Sun to the equinoxes and solstices The first figure of the activity sketches the Earth s orbit and its direction of rotation and revolution 1 The locations on the celestial sphere where the ecliptic and celestial equator cross are called equinoxes Step 2 Daily versus Yearly Motions of the Sky 2 The altitude of the NCP above the northern horizon increases from 0 at the equator to 90 at the North Pole The figure shows it increasing from 0 to 30 to 45 3 Asks for student latitude so answers will vary 4 Asks for number of degrees Polaris would be above the northern horizon so answers will vary Should be the same as the previous answer 5 The motion of the stars around Polaris is due to the rotation of Earth 6 The Sun would stay in each constellation of the zodiac for 1 month if they were evenly distributed along the ecliptic 7 The Sun will still be in Gemini Step 3 Reading Star Maps 8 For locations north of 45 constellations listed could include Ursa Minor Draco Ursa Major Canes Venatici Coma Berenices Leo Virgo Crater Corvus For locations north of 30 add Centaurus 9 The Sun is in Virgo on the autumnal equinox 10 For locations north of 45 constellations listed could include Ursa Minor Draco Lyra Aquila Serpens Scutum Sagittarius Corona Austrina For locations north of 30 add Telescopium 11 Answers will vary as students are asked to compare locations of a constellation at midnight on the spring equinox and describe how its location in the sky changed One example is Draco On the spring equinox the meridian barely goes through its tail but on the summer solstice the meridian cuts through its body and head which are not even visible on the spring map 12 The star map of Figure 1 6 shows the Sun below the celestial equator at noon in the winter 13 The Sun is in Sagittarius on December 21 14 Approximately 3 months have passed between Figures 1 6 and 1 7 15 That time block is about one fourth of a year and Vega moved about one fourth across the celestial sphere 16 The Sun is in Pisces at noon on March 21 Note stars of the constellation Cetus are also close to the equinox in this figure 17 Constellations that lie on the ecliptic in Figure 1 8 include Leo Cancer Gemini Taurus Pisces Note stars of the constellation Cetus are also close to the equinox in this figure 18 The Sun is located above the celestial equator in the summer 19 The Sun is in Gemini on June 21 Step 4 Putting It Together 20 Answers will vary The questions that make up this part should make for a good discussion 21 Students are asked to list three points topics concepts visualizations that the activity covered and then write an essay of around 200 300 words that summarizes what they learned about those points Possible topics students could include in their essays using some or all of the key terms Topics meaning of solstice and equinox rotation versus revolution reading star maps constellations celestial sphere seasons the sky changes there are meaningful dates during a year Concepts Polaris stays in the same position but altitude changes some stars are circumpolar star