A Safe Way to View an Eclipse
The next total solar eclipse is expected to take place on March 20, 2015. Total solar eclipses are a spectacular sight, but viewing the sun with the naked eye or through a standard telescope or binoculars is dangerous. The lens in the human eye will concentrate the sun's light and focus it on the back of the retina, which can permanently damage the eyes to the point of leaving the victim blind.
There are actually several safe ways to view an eclipse. A DIY type can make themselves a long box called a pinhole projector. Less handy people should get a pair of eclipse glasses or a set of welder's goggles rated at least 14.
Eclipse glasses can be bought or rented from the local astronomy club, space museum, or natural history museum. They can also be ordered online.
Eclipse glasses are designed to filter out ultra-violet and infra-red light, plus most visible light. They have an optical density of at least 5, with optical density referring to the ability of a lens to filter out a specific wavelength or a wavelength range. An optical density of 6 means the glasses will allow only one millionth of the light wavelengths through, while an optical density of 1 means the filter will allow one tenth of the light wavelengths through. Where the sun is concerned, the higher the optical density, the better.
Eclipse Glasses are made of a scratch-resistant black polymer that is also used as solar filters in telescopes. They produce an orange image of the sun. Black polymer also has the advantage of being less expensive that the specially treated glass that can also be used to make solar filters.
There are actually several safe ways to view an eclipse. A DIY type can make themselves a long box called a pinhole projector. Less handy people should get a pair of eclipse glasses or a set of welder's goggles rated at least 14.
Eclipse glasses can be bought or rented from the local astronomy club, space museum, or natural history museum. They can also be ordered online.
Eclipse glasses are designed to filter out ultra-violet and infra-red light, plus most visible light. They have an optical density of at least 5, with optical density referring to the ability of a lens to filter out a specific wavelength or a wavelength range. An optical density of 6 means the glasses will allow only one millionth of the light wavelengths through, while an optical density of 1 means the filter will allow one tenth of the light wavelengths through. Where the sun is concerned, the higher the optical density, the better.
Eclipse Glasses are made of a scratch-resistant black polymer that is also used as solar filters in telescopes. They produce an orange image of the sun. Black polymer also has the advantage of being less expensive that the specially treated glass that can also be used to make solar filters.