1. Astronomy from Earth’s Perspective: Before the invention of technology that enable humans to leave earth’s perspective, astronomers relied solely on their observations of the heavens to make inferences about earth’s motions .

3. Explain the difference between the geo- and helio-centric models of the solar system. Helio-centric Geo-centric Earth- centered Sun- centered

6. Geocentric vs. Heliocentric

8. Coordinates in the Sky On earth we use latitude and longitude to locate places. In astronomy we use _______________ and __________________. Altitude Azimuth

9. Coordinates in the Sky Altitude is the angle above the horizon in degrees. (Horizon: imaginary boundary between the sky and the ground)

10. Coordinates in the Sky 90° Zenith The highest angle of altitude is ________ and that is the point directly over the observers head called _______

11. Coordinates in the Sky 0° 360° Azimuth is direction broken down into degrees from _______ to _______ Altitude and azimuth together form a coordinate grid for locating objects in the sky.

18. Ships appear to sink gradually below horizon

24. The least amount of gravity is farther from the center of Earth High Mountains farther from the center of earth – gravity is less

26. Gillism #1: “It’s all a matter of perspective! When you change the way you look at things the things you look at change!”

28. Earth Motions

29. Earth's Motions How long is one rotation of Earth? One day

30. Rotation Revolution Rising and Setting of the Sun Rising and Setting of the Moon The Seasons Changing Constellations Movement of Stars through the sky

31. Earth’s Rotation Earth’s axis is tilted 23.5° from the perpendicular. Earth’s axis is always tilted in the same direction this is called parallelism. AXIS – the imaginary line through the planet from the North Pole to the South Pole

32. Earth’s Rotation The earth rotates counterclockwise when looking down from the north pole. Or from west to east when looking at a side view of earth

33. Tilt of the axis always stays the same – 23.5 ° from a line perpendicular to the ecliptic plane: Parallelism

34. How do you calculate Earth's rate of rotation? One rotation = 360° Time for one rotation = 24 hours 360° ÷ 24 = 15°/hr

37. Finding Polaris

39. Since it is located above our axis of rotation– Polaris is a fixed point in our sky above the North Pole. 90º

44. Locating Polaris – our latitude is 41 °N , Polaris’ altitude will be 41°

46. Am I pointing to Polaris? How can you check to be somewhat sure? To Polaris Zenith = 90 ° above the observer Horizon 42 Degree Angle… Pretty close to 41 Degrees

48. Apparent Daily Motion

55. Star trails looking North Polaris Stars are so far away the appear stationary (not moving). Why do they have this pattern? Earth is rotating.

56. Star trails looking South. Notice that the pattern is different.

57. Are stars the same color? No, look at the different color star trails. Stars also vary in brightness.

58. Circumpolar New York State Mid October 3 4 2 1 2 3 4

60. How many degrees did the stars move from diagram 1 to diagram 2? 30° (2 hours x 15°)

61. How can you find Polaris? It’s the only one that didn’t move

62. What hemisphere must you be in? Why? Northern Because Polaris can only been seen in the North

63. What direction must you be looking? North

64. What direction do the stars appear to move?

65. What causes the stars appear to move?

66. Evidence for Rotation Foucault Pendulum Coriolis Effect

68. No force that makes pendulum rotate – must be earth that is rotating!!!

78. Determining Time of day

79. Since the earth rotations at a predictable rate we can easily determine the time of day when looking at an aerial image of earth on the equinoxes. Label your diagram! Remember lines of longitude all are all in the same time zone

80. Earth’s Revolution

81. Mind Expanding Activity How many days in a year? 365.26 days, Honest look at RT. Leap Year web site The length of time for one orbit around the sun.

82. Mind Expanding Activity How many degrees does the earth travel in its orbit around the sun in one day? Approximately 1 degree (360 ° orbit divided by 365.26 days)

83. Seasons

85. Mind Expanding Activity How many days in a season? 90-91 days Spring = Vernal Fall = Autumnal

88. What is the tilt of the earth’s axis? 23.5 degrees As earth revolves around the sun– the tilt of Earth’s axis does not change producing a cyclical change of seasons…. Click here

89. Label the seasons on the aerial views of earth… Note the position of the shadow!

90. Is distance important to seasonal change? NO! Farthest away on July 4, Closest on Jan. 3. Because Earth’s orbit is a nearly circular ellipse.

91. Reasons for the Seasons Video Clip

92. What changes do we observe during seasons in NY? 1. Sun’s altitude changes with the season. Highest – June 21, Lowest – Dec. 21, But NEVER overhead at our latitude.

93. 9/13/2004 5:33 a.m. N S E W The location: Junction of Stewart Avenue and Hempstead Turnpike in Bethpage, NY. Sunrise times ( actual sunrise ) are all Eastern Standard Time A.E. = Autumnal Equinox W.S. = Winter Solstice S.E. = Spring Equinox

94. 9/13/2004 5:33 a.m. N S E W First observation day: September 13, 2004. This is when my baseline was set.

95. 9/13/2004 5:33 a.m. N S E W First observation day: September 13, 2004. This is when my baseline was set. 5:33 a.m . 9/13

96. 9/22/2004 5:42 a.m. Autumnal Equinox (label as “A.E.”)

97. 10/5/2004 5:55 a.m.

98. 10/13/2004 6:03 a.m.

99. 10/27/2004 6:19 a.m.

100. 11/05/2004 6:30 a.m.

101. 11/30/2004 6:58 a.m.

102. 12/21/2004 7:15 a.m. Winter Solstice (label as W.S.)

103. 1/25/2005 7:10 a.m.

104. 1/25/2005 7:10 a.m. 7:10 a.m. 1/25 Start with a new color for January-April! 11/05 6:30

105. 3/22/2005 5:54 a.m. Spring Equinox label as “S.E.”

106. What changes do we observe during seasons in NY? Sun rise and Sun set positions change with the seasons. South of E/W in fall and winter. North of E/W in spring and summer. Sun rise in DC

107. What changes do we observe during seasons in NY? Day length – Duration of Insolation Longest on Summer Solstice, June 21. (15 hours) Shortest on Winter Solstice, Dec. 21 (9 hours) 12 hours on Equinox for all.

111. Comparing the seasons. Summer Solstice Winter Solstice One year on earth

112. Regents Question

115. Apparent Motion of the Sun

118. “ ALASKA MIDNIGHT SUN” NORTHERN HEMISPHERE FROM MARCH 21 UNTIL SEPTEMBER 21 – SUN DOES NOT SET TIMED PHOTOGRAPHY

119. HOW DOES THE LOCATION the SUN CHANGE DURING THE COURSE OF THE YEAR? NO MATTER WHERE YOU ARE ON THE GLOBE, ON THE EQUINOXES THE SUN WILL ALWAYS RISE DUE EAST AND DUE WEST WHEN THE DIRECT RAYS OF THE SUN TRAVEL NORTH OF THE EQUATOR TO THE TROPIC OF CANCER ON JUNE 21 ST (23.5 °N), THE SUNRISE AND SUNSET POSITIONS WILL MOVE NORTH OF EAST. WHEN THE DIRECT RAYS OF THE SUN TRAVELS SOUTH OF THE EQUATOR ° TO THE TROPIC OF CAPRICORN ON DECEMBER 21 ST (23.5°S), THE SUNRISE AND SUNSET POSITIONS WILL MOVE SOUTH OF EAST

120. Changes in the altitude of the path and horizon position of sunrise and sunset are due to revolution Season Sunrise Sunset Equinox (Fall/Spring) Due east Due west Summer North of east North of west Winter South of east South of west

121. EQUINOXES – DUE EAST

122. SUMMER SOLSTICE NORTH OF EAST

123. WINTER SOLSTICE SOUTH OF EAST

125. Use these rules to complete the activity on page 13

126. Summer maximum altitude of noon sun is 73.5 °, Winter is 26.5° Spring/Autumn: 50.0°

127. Click here for animation!

128. HIGHEST ALTITUDE AT SOLAR NOON AT 40 ° N

129. Changing Altitude of the Noon Sun LONG ISLAND, NEW YORK

130. Insolation

131. Insolation ( click here ) a. Insolation - “IN”-coming “SOL”-ar radi-“ATION” b. The higher the Sun is in the sky, the stronger (more intense) the sunlight is. c. Places near the equator receive the most intense insolation. d. At places near the poles , the Sun never rises high in the sky, so the sunlight is always weak. The Polar Regions receive the least intense insolation. e. During the summer months, the duration, angle, and intensity of insolation are greatest. f. Day=hot; Night= cold (no insolation) g. Summer=hot; Winter = cold

134. Due to the tilt of the Earth’s axis, the sun’s rays are only perpendicular (directly overhead) at noon, between 23.5 ° N and 23.5° S during the year June 21 23.5° N Dec. 21 23.5 ° S March/Sept. 21 Tropic is from the Greek for "turning" describing the Sun's motion at the solstices. Solstice means “sun stops”

136. Your Shadow

137. In NY, the noon sun will always be in the South Sky! So which way will your shadow fall? ___________ ( click here ) Your shadow always changes with the altitude of the sun and time of day! North

138. The length and direction of a shadow depends on Since these both effect the sun’s altitude and the angle of insolation Latitude Time of day,

139. Your shadow will always be opposite of the sun, if the sun is just rising in the east, your shadow will fall west. if the sun is high in altitude, your shadow is small, when it is low in altitude your shadow is long.

140. Draw in the 2pm shadow on the second diagram

141. Five different shadows, A', B', C', D', and E', are cast on a certain day by the post when the Sun is in positions A, B, C, D, E, respectively.

143. Length of day

145. The tilt of the Earth on its axis is also responsible for the day and night length: June 21 st December 21 st What date is it here? What date is it here?

146. Animation: Click here

147. EQUINOX (MEANS EQUAL NIGHTS) 12 HOURS OF DAYLIGHT AND 12 HOURS OF NIGHT

148. Click here !

151. Regents Question

154. Regents Question

157. Constellations are groupings of stars that make an imaginary image in the night sky. They have been named after mythological characters, people, animals and objects. In different parts of the world, people have made up different shapes out of the same groups of bright stars. It is like a game of connecting the dots. In the past constellations have became useful for navigating at night and for keeping track of the seasons.

158. Stars in constellations are often very far from one another but we see them in the same direction in the sky. Big Dipper

160. The 13 constellations the sun appears to travel through during the year In August, at night, you see Sagittarius and Capricornus

161. Different constellations at different times of the year

163. Summer Autumn Winter Spring Scorpio, Sagittarius, Capricorn Aquarius, Pisces, Aries Taurus, Gemini, Cancer Leo, Virgo, Libra

165. Long Island 1 2 3 4 9:00 pm 2 3 4

170. The Moon

172. What are these? Why so many? Why is Earth not like this? Craters No atmosphere weathering, erosion, atmosphere

177. Why Two More Days? Moon’s orbit Earth moving around Sun. Earth Moon Moon has to revolve for 2 more days to get back to the new moon phase. This occurs because the Earth is revolving around the Sun.

178. Dark Side/Light Side

179. Changes in Shape

180. Phases of the Moon

182. Phases Of The Moon

183. What causes the phases of the moon? The moon's revolution around Earth.

184. How long does one revolution of the moon take? 27.3 days How long does one rotation of the moon take? ESRTs p15

186. What phenomenon does this explain? We only ever see one side of the moon.

187. Why does the moon rise later each day? because as the Earth rotates, the moon revolves

188. What phase of the moon is this? New Gibbous New Crescent 3rd Quarter

189. How many hours is the moon visible each day? 12 hours Approximate Times of Moonrise and Moonset moonrise moonset new moon 06:00 AM 06:00 PM waxing crescent 09:00 AM 09:00 PM first quarter 12:00 PM 12:00 AM waxing gibbous 03:00 PM 03:00 AM full moon 06:00 PM 06:00 AM waning gibbous 09:00 PM 09:00 AM third quarter 12:00 AM 12:00 PM waning crescent 03:00 AM 03:00 PM new moon 06:00 AM 06:00 PM

190. What is "waxing"? more of the moon's surface can be seen

191. What is "waning"? less of the moon's surface can be seen

192. The phases of the moon are what type of event? Cyclic

194. Regents Answer

195. Tides & Eclipses Astronomy

196. Tides

199. What causes tides?

201. Tides High High Low Low Caused by Moon’s gravity pulling Earth’s water. Two of each because the Earth rotates. Tides always High in line with Moon. Earth

202. How many tides a day? 2 high tides 2 low tides

203. Why are there not exactly 12 hours between tides? because the moon revolves around the Earth while the Earth rotates

206. During which phases of the moon do neap and spring tides occur?

207. Neap? 1st & 3rd Quarters

208. Spring? New or Full Moon

210. Spring and Neap Tides Sun Sun Neap Tide Spring Tide Quarter Phase – not a large change from high to low tide. New and Full Phase – big change from high to low tide. Water being pulled in two directions. Moon and Sun’s gravity pulling in one direction. Earth Earth

214. Eclipses and Conclusions Video Clip

216. Why don’t we have solar and lunar eclipses every month? The moon’s orbit is tilted 5° from the Earth’s orbit.

217. What’s the difference between solar and lunar eclipses? Solar Lunar Earth goes into moon’s shadow moon goes into Earth’s shadow

222. Solar Eclipse 2010

223. Solar Eclipses through 2020

224. Lunar Eclipse What phase? Full Moon

226. Lunar Eclipse 2010

227. Are We Alone?

228. Home Sweet Home You are here!