1. 教師培訓班
Teacher Training Workshop

2. 時間 地點 活動
09:00 登記,派發教材套,入場
09:00 – 09:10 演講廳 簡介
09:10 – 10:30 講座一 (香港大學理學院科學導師 張師良先生)
1. 介紹金星凌日
2. 觀測金星凌日的歷史及其對科學的重要性
講座二
(可觀自然教育中心暨天文館 許浩強先生)
1. 觀測活動介紹
 觀測太陽安全要點
 觀測金星凌日的要點
 基本記錄、繪圖及攝影
2. 製作
a. 針孔投影盒(連製作)
b. 太陽濾鏡眼鏡製作
c. 雙筒鏡濾鏡製作
分享
 陳樹渠紀念中學 黃炳思老師
 港島民生書院 梁達榮老師
 聖母書院 梁振聲老師
10:30 – 10:40 小休

3. 時間 地點 活動
10:40 – 11:50 分組實際觀測示範
月明泉
(分5組) A. 使用望遠鏡
(下雨時，於黃麗松講堂) a. 投影法
b. 目視觀測(使用濾鏡，包
括望遠鏡及雙筒望遠鏡)
B. 針孔投影盒
C. 太陽投影儀及太陽望遠鏡
D. 太陽漏斗/太陽槍及雙筒
望遠鏡投影
E. 攝影紀錄
11:50-12:00 演講廳 總結及問答
填問卷

4. 培訓班目的：
• 理解及體會金星凌日天象的重要
• 簡單介紹金星凌日背後的原理
• 學校能夠如何及怎樣舉辦活動
• 在技術層面如何觀測金星凌日
• 探討支援方案

5. Two coming historical events
5月21日日環食
香港可見 : 日出至 07:16
環食: 06:07 – 06:10

6. 金星
5月期間
日落時間可見金星
木星
月球

7. Simulations by Stellarium
www.stellarium.org

8. The pre-dawn Venus
• Position of
Venus night
after night at
sunrise
• Symbols at 2
week intervals
The rising Sun
East Credit: Stairways to the Stars, Anthony Aveni

9. Credit: Stairways to the Stars, Anthony Aveni

10. The Dresden Codex : a Maya picture book produced in northern Yucatan about the 11th century
• Venus in a Maya sacred book. The five-page Venus Table on pages 46-50 of the Dresden
Codex showing pictures of the Venus god flinging arrows and his events, dates, intervals,
directions, and resulting omens.
• The Maya had a unique calendar system based on Venus
http://www.famsi.org/mayawriting/codices/dresden.html

11. Path of Venus relative to the Sun
from April 3rd through August 7th, 2004 (top right to bottom left)
evening star
The Sun
morning star
Credit: Tunç Tezel

12. 2012年6月6日 金星凌日
凌日階段 時間 太陽方向/方位角/仰角
Ⅰ 凌始外切 6時11分 東北偏東/068°/6°
不按比例 Ⅱ 凌始內切 6時29分 東北偏東/069°/10°
凌甚 9時31分 西北偏西/081°/51°
Ⅲ 凌終內切 12時31分 西北偏西/278°/88°
注意選擇適當的觀測地點
Ⅳ 凌終外切 12時48分 西北偏西/274°/84°
日出 5時37分 東北偏東/065°/0°

14. 正確的合理期望

15. Transit of Venus happened since the invention of telescope
• 1631 December 7
• 1639 December 4
122 years
• 1761 June 6
• 1769 June 4
105 years
• 1874 December 9
• 1882 December 6
122 years
• 2004 June 8
• 2012 June 6
105 years
• 2117 December 11
Last chance in your life!

16. Orbital configuration of Venus and Earth
軌道周期:
金星 224日
地球 365日

17. Kepler’s laws of planetary motion
• Law of ellipses
– the orbit of a planet about the
sun
is an ellipse with the sun at one
focus
• Law of equal areas
– a line joining a planet and the
sun a
sweeps out equal areas in equal
intervals of time
• Law of harmonies
– the square of a planet’s sidereal
period around the sun is directly
proportional to the cube of the
length
of its orbit’s semi-major axis, a

18. Average distances of planets from the Sun (In AU)
Copernicus Kepler 20th Century
Mercury 0.3763 0.389 0.387
Venus 0.7193 0.724 0.723
Earth 1.0000 1.000 1.000
Mars 1.5198 1.523 1.524
Jupiter 5.2192 5.200 5.202
Saturn 9.1743 9.510 9.539
• 1AU is the Sun-Earth distance
• Relative distance between planets known to good accuracy even
during Kepler’s time
• Absolute scale of the solar system (i.e., exactly how long is 1
AU?) remains unknown

19. The early days
• Ptolemy, Copernicus and Tycho, they all assumed 1AU = 1200
times the radius of the Earth
• Kepler guessed 1AU = 3500 times the radius of the Earth
• They lacked observational instruments and methods to test
their guess

20. Method 1 – a smarter(?) guess
• Measure the apparent size of a planet with a telescope
• Assume a physical size of the planet
• Distance to the planet can be obtained from the ratio of
physical size to the apparent angular size
It is practically accessible, but theoretically no better
than pure guess

21. Method 2 – triangulation (parallax)
• If a planet is observed simultaneously by two
observers separated by large distances, then the
apparent position of the planet among the
background stars would be slightly different.
• If we know the separation of the two observers,
the distance to the planet can be calculated.
• Difficulties: measure of the separation, the
longitude problem, small angle, synchronization
of the clocks
It is prefect in theory, but difficult to
execute 21

23. Sketch of the 1761 transit as seen by Nicholas Ypey.

26. 1874 北京 - James Craig Watson

27. Parallax 視差

28. Angular size VS real size

29. 4 ways of calibrating AU using ToV
1. Observing the different apparent paths of Venus across the face of the Sun seen
from different widely spaced latitudes
2. Measuring the rate (angular velocity) at which Venus crosses the face of the Sun.
The rate is the vector sum of the orbital angular velocity of Venus and the Earth
and the angular velocity of the observing site due to the Earth’s daily rotation.
3. Comparing the absolute times of Venus’s contact with the Sun’s limb, seen from
different places on Earth (Delisle’s method).
4. Comparing the total time for Venus to cross the Sun as seen from different
latitudes, which depends on both the curvature of the Sun’s limb and the
distance moved by the observer due to the Earth’s rotation (Halley’s method).

31. 31

32. d1 = (d1 + d2) sin θ
32

34. A new size of the solar system
• From the transit of Venus on June
3, 1769, the AU was measured to
10% accuracy.
• The size of the solar system turned
out to be 100 times larger than
Ptolemy’s estimate.
• Once the absolute scale (AU) is
fixed, then the size and distances to
the planets can be determined.
• The physical size of the solar system
is finally known.
Estimates of the size of Earth's orbit,
1 AU = 149,598,000 kilometers A.D. 100 - 1769
34
Coming of Age in the Milky Way, Timothy Ferris

35. 講座系列 時間：下午3時-4時30分 地點：香港太空館演講廳
第一講：金星凌日的科學與歷史
日期：2012年5月13日(星期日)
講者：張師良先生（香港大學理學院科學導師）
第二講：金星凌日及日環食現象及觀測
日期：2012年5月20日(星期日)
講者：余惠俊先生（香港天文學會外務副會長）
第三講：金星
日期：2012年5月27日(星期日)
講者：張師良先生（香港大學理學院科學導師）
第四講：太陽系外的凌日現象
日期：2012年6月2日(星期六)
講者：李文愷博士（香港大學物理系副教授）

36. 警告：
太陽觀測活動必須注意安全
不正確觀測太陽會導致永久失明

37. 智能手機 計時 apps

38. 6月6日觀測活動
• 尖沙咀星光大道
• 06:00 - 13:00
• 小型觀測站在網頁公佈
• 網上直播
www.facebook.com/transitofvenushk
transitofvenus.hk
hk.space.museum
roadshow.science.hku.hk