Eclipse is an astronomical event that occurs only when one celestial body’s shadow falls onto that of another. In context of earth, we use the term solar and lunar eclipse mostly. Eclipse is derived from a ancient greek word that means “to abandan” or “to darken”. So, what is solar and lunar eclipse and do they have negative effects on our eyes?
Solar eclipse is a term described as the state, when moon’s shadow falls on earth’s surface. It happens as earth moves into the shadow cast by its natural satellite moon. Likewise, Lunar eclipse is defined as the state when moon comes into the shadow cast by its hosted planet earth. There would be a solar eclipse every month on new moon and there would be lunar eclipse on every full moon, but it doesn’t work that way. Even though the moon’s orbit is around the earth, but due to the non planer and non circular orbit of the moon around earth, eclipses are not a common event.
Misconceptions about eclipse:
Sun emits Extra radiations during the eclipse:
The sun is 15 Millions Kilometers from earth and the moon is 375,000 k.m from earth. The moon coming between sun and earth doesn’t alter the nuclear reaction happening in the sun.
There is a small colored portion in the eye called as “IRIS”. The centred hole of which is defined as “pupil”. The major function of the pupil is to regulate the amount of the light entering the eye and reaching the retina. During a bright sunny day, the pupil are constricted to allow minimum light in the eye so the retina is not overwhelmed by brightness and damage. Whereas, in the solar eclipse, it is cloudy outside which cause our pupil to dilate. The light enters the eye easily. When people look at the eclipse, regardless of total or partial eclipse, your pupils are completely dilated and extremely vulnerable. Light enters your pupils and before your brain can comprehend what has happened, a small amount of exposure to direct sunlight can cause permanent damage to your retinas. The burning corona has nothing to do with the eclipse or radiation. While lunar eclipse is totally safe to look directly with our eyes.
Why is moon red during lunar eclipse ?
It is the same mechanism that cause the sunset/ sunrise on earth to appear red and the sky to appear blue i.e “Rayleigh scattering”. The red orange light is the refracted light from earth that hits the moon and it appear as blood moon.
What to do and what not to ?
The solar retinopathy is the term defined for the damage caused to eyes during eclipse. Avoid looking at the sun directly. Use a dark goggle that protects your eyes from harmful light of sun. Avoid using cameras or smart phone to look at the eclipse. Don’t view through view finder, binoculars or telescopes.
Safest way is to make a d.i.y project of pin hole projector. Make hole in a paper and let the light fall on the paper placed on the ground.(Not to be confused with looking eclipse with pinhole). Recorded videos can be watched.
What if you you see blur after you look at the eclipse?
The best possible thing to do is to avoid yourself from doing so. The damage is irreversible and Incase you see blurry, you need to visit an Ophthalmologists as soon as possible.
Notes and Reference: National Aeronautics space Administration, American Academy of Ophthalmology.
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i CARE EYE CLINIC Nagpokhari Marg, Kathmandu Phone: 01-4445746, 01-6911700 Available Doctors: 1. PROF. DR. SANDUK RUIT, MD, FRACO 2. Dr. Shrijana Adhikari, MBBS, MD (Pediatric & Strabismus) 3. Dr Leena Bajracharya, MBBS, MD (Cornea Specialist) 4. Dr Indira Poudyal, MD, Glaucoma Specialist 5. Dr Raba Thapa, MBBS, MD, Ph.D. (Vitreo Retina Specialist) 6. Dr Purnima […]
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