1. Astronomy 4230 天 文 学 概 论 A Brief Course of Astronomy

2. 张景波 哈尔滨工业大学物理系 哈尔滨市天文爱好者协会 Location: L331 Tel: 86414104 30hours 3hours/times Sunday, 1st-3rd Class Room: A413 http://jinux.hit.edu.cn E-mail:jinux@hit.edu.cn

3. Lectrure 1 Sky and Cosmos

4. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 宇宙的尺度

5. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 天球

6. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 地平坐标系

7. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 赤道坐标系

8. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230

9. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 低平高度与纬度的关系

10. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 星座

11. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 星座

14. 猎户座 和 大犬座

15. 大熊座和北斗七星

16. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 太阳的运动

17. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 太阳的表面特征

18. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 黄道十二宫

19. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 太阳与四季

20. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 太阳日和恒星日

21. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 月亮的运动

22. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 日食和月食 Eclipsis

23. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 月食 Lunar Eclipses Umbra: Inner core of total darkness –The disc of the Sun is completely blocked. Penumbra: Outer, partial shadow –Sun's disc is only partly blocked, with a bit peeking over the edge. Lunar Eclipses are when the Moon passes through the shadow of the Earth. They only occur during Full Moon when the Earth is between the Moon and the Sun.

24. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Penumbra Sun Earth Umbra 月食原理

25. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 月食原理

26. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Lunar Eclipses Total Length of Earth’s Umbra – ~1.4 Million km long –About 3.7x the mean Earth-Moon distance. Umbra's width at the distance of the Moon –9000 km –~2.6x the Moon's diameter.

27. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Three Types of Lunar Eclipses Total Lunar Eclipse: –Entire Moon is within the Earth's umbra. –Can spend up to 1 h 40 m in the umbra –Whole show can last ~6 hours Partial Lunar Eclipse: –Only part of the Moon enters the umbra. Penumbral Eclipse: –Moon misses the umbra completely, only passes through the penumbral shadow.

28. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Three Types of Lunar Eclipses

29. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230

30. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Solar Eclipses occur when the Earth passes through the shadow of the Moon. They only occur during New Moon when the Moon is between the Earth and the Sun. Totality ‘incredibly’ spectacular The Moon's umbra is only 380,000 km long: –Just long enough for the tip to touch the Earth. –But not large enough to cover the entire Earth. –Solar Eclipses seen only where the shadow passes overhead. 日食 Solar Eclipses

31. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230

32. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 日食原理

33. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Types of Solar Eclipses Total Solar Eclipse: –The observer is inside the Moon's umbra. –The Moon completely covers the Sun. Partial Solar Eclipse: –The observer is inside the Moon's penumbra. –Only see part of the Sun covered by the Moon. Annular Eclipse: –The Moon is at or near apogee, and so is too small to cover the Sun –The Moon's umbra does not touch the Earth, so observers in the shadow path see the Sun as a ring ("annulus").

34. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Total Solar Eclipses Total Solar Eclipses are localized and short: –The Moon's umbral shadow is at most 267 km across on the Earth. –Totality lasts at most about 7.5 minutes. –Only observers in the umbra see a total solar eclipse. –Observers in the penumbra see a partial solar eclipse. –Everyone else sees nothing.

35. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Rare Events – Why ? Eclipses are rare : –From a given location on the Earth you see a Total Lunar Eclipse every 3 years (or so). a Total Solar Eclipse every 360 years. Why not : –Each full moon = lunar eclipse –Each New Moon = solar eclipse ??

36. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Why Eclipses are rare Moon’s orbit not perfectly aligned with Ecliptic : – ~5° tilt from Ecliptic –Where the moon's orbit crosses the Ecliptic defines the "Line of Nodes" –Only get eclipses when the line of nodes and the Sun line up at Full or New Moon.

37. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 The Eclipse Year Line of Nodes aligns with Sun every 346.6 days. ("Eclipse Year“) But, it must be a Full or New Moon when the nodes line up to have an eclipse. This happens only very rarely. Check out Fred Espenak’s Eclipse page http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html

38. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 日地月关系

42. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 行星的运动

43. 水星 Mercury

44. 金星 Venus

45. 地球 Earth

46. 火星 Mars

47. 木星 Jupiter

48. 土星 Saturn

49. 天王星 Uranus

50. 海王星 Neptune

51. 冥王星 Pluto

52. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 行星的运动 Mercury Venus Mars Jupiter Saturn

53. Star-like Appearance close to Ecliptic Two separate cases : –always close to Sun (Venus, Mercury) –appearance at any point of time during night/day (Mars, Jupiter, Saturn)

54. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Mercury, Venus, ‘inferior’ planets Inferior Conjunction: –Planet is between the Earth and the Sun. Superior Conjunction: –Planet on the other side of the Sun from Earth. During both conjunctions, the inferior planet appears to rise and set with the Sun. Maximum Eastern Elongation: –Planet is furthest East of the Sun as seen from the Earth (28º Mercury, 47º Venus) –Rises & sets after the Sun ("evening star") Maximum Western Elongation: –Planet is furthest West of the Sun as seen from the Earth. –Rises & sets before the Sun ("morning star") 内行星 Inferior Planets

55. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 金星的视运动

56. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Opposition: –Planet is opposite the Sun in the sky. –Rises as the Sun sets –Highest in the sky at midnight. Conjunction: –Planet is on the same side of the sky as the Sun. –Rises with the Sun Eastern Quadrature: –Planet at right angles to the Earth-Sun line. –Planet rises at noon, sets at midnight. Western Quadrature: –Planet at right angles to the Earth-Sun line. –Planet rises at midnight, sets at noon. 外行星 Superior Planets

57. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 火星的视运动

58. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 行星的视运动 In general, the planets move eastward relative to the "fixed" stars. –Called "Direct Motion". –Motion is non-uniform (not at the same speed). Sometimes, however, the planets appear to –Slow down & stop! –Start moving westward, or RETROGRADE, –Slow down & stop again, –Resume moving eastward again. Apparent retrograde motion is observed in all planets.

60. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Summary of Celestial Motions –Fixed Stars: Uniform daily motion about the celestial poles. –The Sun: Daily motion around the celestial poles (rising and setting). Eastward drift along the Ecliptic over a year, a little faster in winter, slower in summer. –The Moon: Daily motion around the celestial poles. Eastward motion near the Ecliptic over a month. Summary

61. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Summary of Celestial Motions –The Planets: Daily motions about the celestial poles. Generally eastward motion near the Ecliptic at different speeds for each planet. Occasional westward "retrograde" motions. Superior Planets are brighter at opposition, fainter at conjunction. Summary

62. J.B.Zhang Mar 5, 2006 Lecture 1, Astronomy 4230 Homework 1. 有一颗恒星 1 月 1 日在晚上 10:00 时升起，那 么它于下列日期将在什么时候升起？ (1) 1 月 4 日 (2) 1 月 30 日 (3) 7 月 1 日 E-mail: jinux@hit.edu.cn before mar 12