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Eclipse Viewers

 

Since prehistoric times men have looked to the sky with the naked eye and, through long-term observation, some of them may even have been able to predict eclipses.

 

This effort also led to a greater understanding of the earth beneath men's feet. The Greek astronomer Aristotle (384-322 BC) noted that as the earth casts a round shadow on the moon during an eclipse, then logic dictates that our planet must be a sphere.

 

  Pyramid drawing from a certificate

The Great Pyramid in Egypt may have been used as an observatory. The entrance to the King's Chamber was in direct alignment with the axis of the earth such that a horizontal mirror placed in the chamber would have reflected the North Star. The Pyramid and the Sphinx are pictured here on this qualifying certificate for the Worshipful Company of Spectacle Makers from 1929.

 

According to one modern theory the worship of the solar falcon god Horus and, consequently, the Eye of Horus symbol were inspired by the total solar eclipse's striking similarity in appearance to a gigantic eye staring down from the sky and the fact that during some total solar eclipses a bird-like form may be perceived within the sun's corona. You can learn more about this interesting theory at the Eye of Horus Symbol website or more about the symbol as a lucky charm on our own Eye of Horus page.

 

According to Ptolemy's Almagest, Hipparchus of Rhodes (fl. 2nd c BC) compiled a record of eclipses of the moon that had been observed in Babylon over the preceding six centuries. During an eclipse the sun and moon come directly in line with the earth so Hipparchus' list of lunar eclipses was crucial to his study of solar and lunar movements.

 

The uneducated masses, however, continued to misunderstand eclipses and developed an exaggerated respect for those members of an elite with the power to foretell such fearful events.

 

 

Eclipses and Navigation

 

Hipparchus suggested that navigators could use tables of lunar eclipse times as viewed from different cities to determine longitude. In practice these events occurred too infrequently for the method to be of much use. With the advent of telescopic observation Galileo considered reviving the idea, but with reference to the satellites of Jupiter rather than the earth's moon since these experienced more frequent eclipses. By the late seventeenth century such tables existed but were effective only for navigation on land.

 

  French eclipse satirical print
 How not to view an eclipse

 

This tremendous satirical print shows an eclipse taking place in 19th century France. One man stares at it directly through a telescope; a woman concludes that she will get a better view by perching on someone's shoulders...he's a clown. More sensibly, another man is viewing the eclipse indirectly in a large bucket of water. It is unlikely that the tethered pets are happy....they would have been better shut indoors.

 

Caricatures du Jour - Les Amateurs D'Eclipse. Lithograph print by the Van Lier brothers from the French Album Charivarique. 19th c. (You can see this print on one of our College Meeting Room Tours).

 

 

***Viewing a solar eclipse is potentially hazardous and should only be attempted with caution. You should never look directly at the sun!***

 

  Prototype eclipse viewer
Some of these special viewers relate to the total solar eclipse which was visible in Great Britain and parts of Western Europe on 11 August 1999. The eclipse took place at 12.30pm CET. The advice of optometrists at the time was that absolute reliance could not be placed on such viewers as there was a theoretical risk of them perforating. Lasting retinal damage was incurred by a small number of people as a result of the event (though not through using viewers of this type).

 

Solar eclipse viewing device (prototype) in black-painted wood with the edges sealed by electrical insulation tape. Great Britain (c.1998). This object was subjected to investigation by experts attached to the Professional Standards team at the College of Optometrists. It is a form of indirect viewer working on a periscopic principle, intended to cast a shadow on a white card. To the best of the MusEYEum's knowledge it never resulted in a finished product. In the event, many people in Britain fabricated their own such devices e.g from cereal packets.

 

  Eclipse viewing glasses 2
Solar eclipse viewer (right) made by Swan Packaging Ltd. The frame is of black cardboard to suggest a suitably astronomical theme. It has an elongated side handle as this viewer was designed to be held in front of the face rather than worn like spectacles. The instructions are in French as this particular example was made in England for the French market. Almost identical viewers were branded with the 'Britannia' name for use in Great Britain (1999).

 

Partial Eclipses can be viewed almost all the time from somewhere in the world if you are prepared to travel. There was a total solar eclipse visible from Egypt on March 29th 2006.

 

  Eclipse viewing glasses 3
  Eclipse viewing glasses 4
  Eclipse viewing glasses
Solar eclipse viewing glasses (left) made by Thousand Oaks Optical of California. The bright orange cardboard frame is suggestive of the sun. American (1999).

 

Solar eclipse viewing glasses (right) made by Essilor. The museum possesses two of these pairs with blue cardboard frames. They feature drop-end sides, allowing them to be worn like spectacles. They were accompanied by an illustrated colour leaflet. French (1999).

 

Solar eclipse viewing glasses (left) with a shiny silver cardboard frame. The round eye shapes represent dark moons, enclosing star-shaped film filter lenses. French (1999).

 

 


 

 

  Lunar eclipse 2007
Viewing a lunar eclipse (eclipse of the moon) does not carry with it the same safety concerns. It is perfectly safe to view it directly and take photographs such as this one of the total eclipse of the moon viewed from Central London in the late evening on Saturday 3rd March 2007. Clear skies meant that it could be seen with the naked eye from the centre of town. It was reportedly the best example of this occurence for over ten years. In a lunar eclipse the light of the sun is completely blocked from reaching the moon by reason of Planet Earth being in the way, but the moon is still illuminated to a low degree by atmospheric reflections. The scattered sunlight is reduced in such a way that its red wavelengths predominate and it is these which reflect off the lunar surface to give it its coppery red colour. If the 'Man in the Moon' was looking back at us the earth would have appeared completely black with a just a bright red disc glimmering around it...but he'd have needed to take eye safety precautions as soon as the period of totality ended.

 

 


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