Category

Observing a Solar Eclipse

Introduction

We attempt to observe a solar eclipse

　A solar eclipse occurs when the Sun, Moon and Earth line up, in this order, so that as observed from the Earth, the Moon passes in front of the Sun. Here we introduce a simple observing method which can be used as a classroom teaching aid.

What is a solar eclipse?

　During a solar eclipse, sometimes the Sun is completely obscured, while at other times the Sun is partially covered but still visible. What is happening during the phenomenon?
Try to explain this by drawing a diagram.

Solar Eclipses...

　When the Sun, Month and Earth are in a straight line, as viewed from the Earth, the Moon hides the Sun.

　The Sun is approximately 400 times larger than the Moon. The Sun is a vast body. But the Sun is about 400 times further away from the Earth than the Moon is. Consequently, as viewed from the Earth's surface, the Sun and Moon appear the same size.
There are three different kinds of solar eclipse:

• The Total Solar Eclipse: The Sun and Moon are lined up perfectly, the surface of the Sun is hidden and the gaseous solar corona is visible.
  
• The Annular ("Ring") Solar Eclipse: The Sun and Moon are lined up perfectly, but the Moon appears slightly smaller than the Sun, so the edge of the Sun's surface protrudes around the edge of the Moon's disk.
  
• The Partial Solar Eclipse... The Sun and Moon are not perfectly aligned, and part of the Moon's disk moves across the face of the Sun, so that the Sun is partially obscured.

Observing Method

Things to Prepare

　Solar observing visor

Sun shade for Nakamura science solar observation SF-105N Filter No. 13 Visible light transmission 0.00072% UV transmission (313nm) 0.00% (365nm) 0.05% IR transmission 0.4% max In addition to this visor, numerous different kinds of solar filters are available.

What to expect

• How much of the Sun needs to be obscured before an eclipse becomes visible?
  (30 seconds, 5 minutes, 15 minutes, 2 hours, 1 day)
  
• What will be the appearance of the eclipsed sun? Draw your prediction.

Your Observations

　Use the Sun visor when observing the Sun directly.
　Sketch the shape of the Sun you observe every five minutes.
　You can hurt your eyes if you look at the Sun directly without protection!

Discussion of Observations

Sketching your solar eclipse observations

2004 Oct 14 in Sendai

（１１：３０）	（１１：３５）	（１１：４０）
（１１：４５）	（１１：５０）	（１１：５５）

Discussion

• How much of the Sun was hidden at maximum eclipse?
  
• How long did the eclipse last in total?
  
• Now you will understand how eclipses occur.

Future Eclipses

Future Solar Eclipses to 2010

　Data from the Japanese National Observatory
　(Below are shown the times of maximum eclipse in Japanese time. The approximate area where the eclipse is visible is given in brackets. For total and annular eclipses, only the region where a total or annular eclipse is visible is shown. For partial eclipses, the entire area where an eclipse is visible is shown.)

• 2005-10-03 Annular Solar Eclipse (Europe and Africa)
  
• 2006-03-29 Total Solar Eclipse (Africa and western Asia)
  
• 2006-09-22 Annular Solar Eclipse (South America and Atlantic Ocean)
  
• 2007-03-19 Partial Solar Eclipse (East Asia, Russia and part of Japan)
  
• 2007-09-11 Partial Solar Eclipse (South America and Antarctica)
  
• 2008-02-07 Annular Solar Eclipse (Antarctica)
  
• 2008-08-01 Total Solar Eclipse (Arctic Circle, Russia and China)
  
• 2009-01-26 Annular Solar Eclipse (Indian Ocean and Indonesia)
  
• 2009-07-22 Total Solar Eclipse (India, China, Japan (Ryukyu Archipelago) and Pacific Ocean, with partial eclipse visible across Japan)
  
• 2010-01-15 Annular Solar Eclipse (Africa, Indian Ocean, China, Southeast Asia and Japan at sunset)
  
• 2010-07-12 Total Solar Eclipse (South Pacific Ocean)

Worksheet Collection

　These worksheets were used at Yagiyama Primary School for solar eclipse observations.

Worksheet	HTML	PDF
Pre-Eclipse Expectations	Worksheet 1
Report of Observations	Worksheet 2	255