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Solar viewer (also known as solar viewing glasses or solar eclipse glasses) are special eyewear designed for direct viewing of the
Solar viewer (also known as solar viewing glasses or solar eclipse glasses) are special eyewear designed for direct viewing of the Sun
The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
. Standard sunglasses are unable to filter out eye damaging radiation. Solar viewers are required for safe viewing of solar events such as eclipses
An eclipse is an astronomical event that occurs when an astronomical object or spacecraft is temporarily obscured, by passing into the shadow of another body or by having another body pass between it and the viewer. This alignment of three ce ...
. The recommended optical density of this eyewear is 5.
Safety
According to the American Astronomical Society (AAS) products meeting theISO
ISO is the most common abbreviation for the International Organization for Standardization.
ISO or Iso may also refer to: Business and finance
* Iso (supermarket), a chain of Danish supermarkets incorporated into the SuperBest chain in 2007
* Iso ...
12312-2 standard avoids risk damage, and issued a list of reputable vendors of eclipse glasses. The organization warned against products claiming ISO certification, or even citing the exact standard number, but not tested by an accredited laboratory, or those bearing incomplete certification information. Another problem was counterfeits of reputable vendors' products, some even claiming the company's name (such as with American Paper Optics which published information detailing the differences between its glasses and counterfeits).
Eyewear made prior to 2015, may have a 3-year use limit before they can no longer effectively filter out UV radiation. Starting in 2015, products made with ISO 12312-2 can be used indefinitely as long as they have not been damaged by scratch or tear.
Counterfeit eclipse glasses
In the months leading to thesolar eclipse of August 21, 2017
The solar eclipse of August 21, 2017, dubbed the "Great American Eclipse" by the media, was a total solar eclipse visible within a band that spanned the contiguous United States from the Pacific to the Atlantic coasts. It was also visible as a ...
, counterfeits of light-filtering glasses for solar eclipses began proliferating, leading to public health
Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...
issues. Effective eclipse glasses filter visible, ultraviolet, ''and'' infrared light. The eye's retina lacks pain receptors, and thus damage could occur without one's awareness. Includes photos of genuine and fake eclipse glasses.
The AAS said determining whether an eclipse viewer was safe required a spectrophotometer and lab equipment, but often the user should see nothing through the filter except for the Sun, sunlight reflecting off of shiny metal, or intense light sources such as an LED flashlight.
Andrew Lund, the owner of a vendor of eclipse glasses, noted that not all counterfeit glasses were necessarily unsafe. He stated to ''Quartz
Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...
'' that the counterfeits he tested blocked the majority of harmful light, concluding that "the IP is getting ripped off, but the good news is there are no long-term harmful effects."
On July 27, 2017, Amazon required all eclipse viewing products sold on its website have a submission of origin and safety information, and proof of an accredited ISO certification. In mid-August 2017, Amazon recalled and pulled listings for eclipse viewing glasses that "may not comply with industry standards", and gave refunds to customers who had purchased them.
See also
* Astronomical solar filter *Eclipse chasing
Eclipse chasing is the pursuit of observing solar eclipses when they occur around the Earth. Solar eclipses must occur at least twice and as often as five times a year across the Earth. Total eclipses may occur multiple times every few years.
A pe ...
* Solar telescope
* Transit of Mercury
frameless, upright=0.5
A transit of Mercury across the Sun takes place when the planet Mercury passes directly between the Sun and a superior planet. During a transit, Mercury appears as a tiny black dot moving across the Sun as the planet obs ...
* Transit of Venus
frameless, upright=0.5
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a tr ...
References
{{Eyewear Eyewear Ophthalmology Prevention Fashion accessories Solar viewing glasses 2010s fashion