High quality glasses for viewing a solar eclipse
The next solar eclipse visible in the United States will take place next year on September 1, 2016. On average there is a solar eclipse event once or twice a year, visible somewhere on the globe. There are also solar eclipses visible somewhere in the United States at least once a year. The one in August of next year promises to be a spectacular total eclipse that will draw scientists from around the globe. Many people are busy ordering high-quality solar eclipse glasses for this event.
The Wonder of Solar Events
Total solar eclipses are very spectacular, although each event has its own individual quirks. At the peak of the eclipse that lasts a mind-blowing five minutes or so. You can see the way the sun actually looks and how it functions without the distraction of the blinding brightness from the center of the disk. Seeing a full solar eclipse is truly a once-in-a-lifetime experience that gives you a completely new perspective on the universe.
Even a partial eclipse of the sun is a clear demonstration of the way the solar system works. With good eye protection, you can see the dark face of the moon as a real object passing in front of the sun.
You will need eye protection to view any partial eclipse and all of the eclipse events except the very full eclipse point when light levels are at a minimum. As soon as the sun comes out of the eclipse, eye protection has to be returned.
A transit of Mercury or Venus passing in front of the globe of the sun is also a fascinating astronomical event because you can see the globe of one of the two inner planets as it makes its journey around the sun as does the Earth. Transits are hard to see because the disks of the planets are so very small against the sun, but with proper eye protection and a pair of binoculars, you can see it.
However, no one can view the entire solar eclipse or planetary transit without eye protection. You need that keep the harmful solar radiation out of your eyes while you see the magic of the solar flares and the corona that appear as the eclipse takes place.
You can make a safe viewing alternative to eclipse-safe lenses by using a pinhole camera or a telescope’s projection devices to project an image onto cardboard or a screen and viewing the event indirectly. However, projections rarely provide the detail and sharpness of a direct view through safely filtered glasses.
According to NASA, you can safely view any of these solar events, but you need very high-density filtration for your eyes. The equivalent of number 14 welder’s glass or darker. Even ordinary welder’s goggles are less than number14 filtration and should not be used. Solar eclipse glasses have special safety filters that permit safe viewing. The visor of the spacesuit designed by NASA for use at the space station is covered with a thin layer of gold which offers filtration beyond that of a #14 welder’s helmet.
Solar Viewing Filters
Most solar eclipse quality lenses have a thin layer of chromium alloy or aluminum deposited on the surfaces of the lens. The layer of metal lets less than .003 percent of visible light and no more than .5 percent of the near-infrared radiation to pass through.
A pair of high-density safe eclipse glasses that filters out more than 99 percent of visible light also allows you to view solar features like sunspots.
Safe eclipse or solar viewing glasses filter out
- All ultra-violet (invisible short-wave and high frequency) light waves.
- All harmful infra-red (invisible high-energy, long-wavelength, low-frequency) light waves.
- 99.99 percent of visible light.
- Solar viewing materials should be CE Marked (as recognized in Europe and the USA) and manufactured according to international conventions.
- The best solar viewing glasses are manufactured under ISO (International Organization for Standardization) certified manufacturing standards.
- High-quality eclipse glasses made of glass rather than plastic will hold their filtration properties longer and will not fade. Plastic glasses contain instructions that warn “negative effect on usability for their stated purpose…may be caused by handling and storage conditions…”
- It is critical that glasses protect the eyes when viewing the sun not be compromised by poor standards. Eyesight itself is at stake.
Effects of Poor Protection
Ordinarily, we do not look at the sun for more than a split second and even then we are struck by the effect of sunlight on our eyes.
- The pupils try to adapt, closing quickly to their minimal aperture. But the bright image causes an immediate adaptation effect on the retina which temporarily turns off the nerve transmission to the brain and makes a negative image of the sun that does not immediately fade even after you turn your head away.
- Prolonged exposure to the sunlight literally burns the retinal tissue causing lasting or permanent “eclipse blindness” or retinal burns.
- Exposure of the retina to intense visible light damages the light-sensitive rod and cone cells.
- The photochemical retinal damage from the visual light intensity will be accompanied by thermal injury from the near-infrared light that causes heating and literally cooks the exposed tissue in the eye.
- The retinal damage occurs without any feeling of pain because there are no pain receptors in the eye. The visual effects may not show up for at least several hours after the damage is done.
The Phillips family has a history of more than 100 years in the optical business, making optical glass and filters. Please contact us to learn more.