Unfortunately, the news media are very bad at telling us about upcoming eclipses. The usual thing is that they tell us a solar eclipse is happening... tomorrow. Since it can takes weeks to order eclipse glasses, plan school lessons, and so on, the sad result is that a lot of people — particularly schools — fail to get the best out of the amazing spectacle.

This site is here to help! The home page lists prominent upcoming eclipses that you should consider planning for; and the next 10 years page shows all eclipses coming up in the next 10 years. And finally this page tells you how you can make simple preparations to get the most out of an eclipse. By researching the proper place and time to see the eclipse, and by setting up some simple supplies in advance, you can have a safe and enjoyable eclipse-watching experience.

The Date, Time and Place


Visibility of a typical total solar eclipse — be in the red band!

First of all, make sure you have the dates and times right; the headline date of an eclipse is not necessarily the date it happens on in your local tine zone. This site can show you all the timings of eclipses in your local time, as long as you have selected your time zone in the settings; so do that, and then look at the detail page for the eclipse you're interested in to get the timings listed for your time zone.

For lunar eclipses, the eclipse timings are the same for everyone in the world. For solar eclipses, though, the overall timings are not the time when the eclipse will be seen in your location. Eclipse pages will usually give a more detailed breakdown of when the eclipse will be seen in a given location, and the eclipse maps have markers showing the timings for specific locations along the eclipse path.

The Observing page has advice on the best place to be for a given eclipse — both in terms of which parts of the world will see the eclipse, and also how you can find a good viewing location in your area.

Lunar Eclipses


The total lunar eclipse on the 4th of April 2015.

A lunar eclipse is relatively easy to plan for. There's really no special equipment required, and as long as you have a good view of the Moon, location isn't critical, as the eclipse can be seen from half the Earth.

You're going to be out at night, so think about the cold — even when the temperature isn't terribly low, when you're outside and relatively inactive in the small hours of the morning, it can feel very cold. So have warm clothes and a flask of something hot to drink.

Other than that, just enjoy the spectacle! If you're going to try to photograph or video the eclipse, remember that the full Moon starts very bright, then gets a lot dimmer during a total eclipse — by 15 to 20 stops or so. And it moves faster than you might think; it will move its own diameter in about 2 minutes.

Solar Eclipses

For any solar eclipse, the most important thing to thing about is eye safety. The precautions you need to take are pretty simple, and generally should not stop you enjoying the eclipse; however, if you are not confident that you, or people you are responsible for, can correctly follow the safety precautions, then it would be best to stay indoors and watch the event on TV or the internet.


A simple binocular-based eclipse projector.

For the great majority of people, a solar eclipse is a fascinating phenomenon, and should not be missed; so prepare in advance by having proper viewing equipment set up. Eclipse glasses are the most basic; these can easily be found online. Just order them a few weeks in advance so that you have them in time. Make sure to buy them from a reputable source; fake goods of all kinds are abundant, and real eclipse glasses need to block out 99.997% of the visible light.

A sun projector is a fantastic way to view a solar eclipse. Not only is it a safe and fun way to see any non-total solar eclipse, building one is an interesting project and a great opportunity for teaching basic optics and engineering. Our Observing page has information on various types of projector; setting one of these up is quite easy, as long as you have the materials and time to experiment in advance.


Projecting a partial Solar Eclipse and sunspot region.

A sun projector can be used for viewing the Sun at any time, and can be used for viewing sunspots and active regions; so start experimenting well in advance, and you'll be prepared for the eclipse. Just remember to never look through the projector — only look at the projected image.



Teaching

An eclipse of any kind is a great opportunity to get kids engaged with the sciences, and to teach them about optics, engineering, and astronomy. For a solar eclipse in particular, you obviously need to be prepared to deal with the safety and logistical issues, and I hope this page is a little help. Beyond that, here are some simple talking points that could be discussed in the weeks leading up to an eclipse. At the end you'll find links to some more teaching resources from the internet.

Safety

Our Eye Safety page has some relevant tips; but for information by real experts, I strongly recommend that you read these guides (if nothing else, read Prof. Chou's paper):

Eye Safety During Solar Eclipses, by Fred Espenak
An essential guide to safety while viewing a solar eclipse, from the experts at NASA.
Eye Safety During Solar Eclipses, by Professor B. Ralph Chou, MSc, OD
A more detailed look at the safety issues in observing solar eclipses, by B. Ralph Chou, Professor Emeritus in Optometry and Vision Science, University of Waterloo.
Solar Eclipses and Public Education
An interesting article on the difficulties of properly communicating the dangers of eclipses, by Professor Jay M. Pasachoff, Field Memorial Professor of Astronomy at Williams College, MA.
OK, Look Directly at a Total Solar Eclipse
A discussion on safety in solar clipse viewing, by Dick Land of The Schepens Eye Research Institute.
B. Ralph Chou, Professor Emeritus
A profile of Professor Ralph Chou, with links to his writings on eye safety with respect to optical radiation.

Some suggestions for talking points:

  1. How bright is the Sun, compared to the full Moon?
  2. What happens if you stare at the Sun? Does it hurt straight away? What about later?
  3. What could happen if you looked at the Sun through a lens (binoculars, telescope, camera viewfinder)?
  4. What do you need to look at an eclipse directly?
  5. Do sunglasses protect you from the Sun when just being outside normally? What about when you look straight at the Sun?
  6. What are some safe ways to view an eclipse?

Astronomy

Find some information on these subjects in the Science pages.

  1. How do the Earth and Moon move relative to each other, and to the Sun?
  2. Why do eclipses happen?
  3. How big is the Sun? How does it compare to the Earth and Moon?
  4. How big does the Sun appear to be relative to the Moon? Why?
  5. What is happening during a solar eclipse?
  6. What is happening during a lunar eclipse?
  7. Why don't eclipses happen every month?

Optics

  1. How does a pinhole camera work?
  2. How does a lens-based camera work?
  3. How do real cameras combine both these ideas?
  4. How can we use these to see the Sun?
  5. How does a pinhole projector compare to a lensed projector (e.g. using binoculars)?

Try constructing a simple projector — it can be as simple as a card with a hole in it held in front of a wall, or a pair of binoculars held in front of a piece of card. You can try it out on any sunny day.

Get more sophisticated with a cardboard tube, with a pinhole on one end and a screen fixed in front of the other. Or use binoculars on a tripod with a screen held behind the eyepiece. Compare the results from the two types of projectors. Which is better? Why?

Use a projector to look for sunspots; if there are any, sketch the image of them and compare with images online, such as the latest SOHO live Sun image. Why is the image from the projector inverted?

Making

  1. How could you design a projector for viewing an event that lasts an hour or more?
  2. How fast does the Sun or Moon move across the sky?
  3. What kind of motion does a Sun projector need to track the Sun?

Try building different types of projector with equatorial mounts, to make tracking the Sun easier. To get really sophisticated, try motorising them.

More Classroom Resources

Our Star the Sun
Lesson plans for teaching the Sun, including several sections on eclipses.

Kidseclipse: teaching section
Lesson plans for teaching eclipses at an elementary level.

Eclipse Activities
Lessons plan and worksheets that can be used in the classroom to enhance understanding of eclipses.