The scintillating cosmic phenomenon of a total solar eclipse will be visible to millions of people across parts of Greenland, Iceland, northern Russia, Spain and Portugal on Aug. 12. The best way to prepare for safe viewing of the stellar lineup is to locate a pair of eclipse glasses. Sunglasses won’t be enough to protect your eyes for direct viewing of the spectacle. A total solar eclipse occurs when the moon passes between Earth and the sun, completely blocking the sun’s face. A partial eclipse will pass across the northern United States, Canada, much of Europe and northwestern Africa. The only time it’s safe to view the sun without eye protection is during the totality of a total solar eclipse, or the brief moments when the moon completely blocks the light of the sun, according to NASA. Any hint that light is reappearing means it’s time for eye safety measures. “Even the 1% of the Sun’s surface that remains visible emits enough radiation to permanently damage the eye’s light-sensitive cells,” according to the Institute of Astrophysics of the Canary Islands, which is located along the 2026 eclipse path. Directly staring at the sun can result in blindness or disrupted vision. During the 2017 total solar eclipse, a young woman was diagnosed with solar retinopathy, retinal damage from exposure to solar radiation, in both eyes after viewing the eclipse with what doctors believe were eclipse glasses not held to proper safety standards. There is no treatment for solar retinopathy. It can improve or worsen, but it is a permanent condition. Sunglasses won’t work in place of eclipse glasses or solar viewers, which are 100,000 times darker and held to an international safety standard. While sunglasses can protect our eyes from harmful UV rays during everyday activities, they are not intended for use when looking directly at the sun. The lenses of solar eclipse glasses are made of black polymer, or resin infused with carbon particles, that blocks nearly all visible, infrared and ultraviolet light, according to The Planetary Society. Sunglasses don’t block infrared radiation. Put on your eclipse glasses before looking up and remember to turn away from the sun before you remove them again. Always keep an eye on any children wearing eclipse glasses to make sure they don’t remove them while looking at the sun. If you normally wear eyeglasses, keep them on and put eclipse glasses over them or hold a handheld viewer in front of them, the American Astronomical Society advises. Don’t look at the sun through any unfiltered optical device — camera lens, telescope, binoculars — while wearing eclipse glasses or using a handheld solar viewer, according to NASA. Solar rays can burn through the filter on the glasses or viewer and can cause severe eye damage, given how concentrated the rays can be through an optical device. It’s also possible to use welding filters to view the eclipse safely because the international safety standard was partially derived from using such filters to view the sun. Auto-darkening or adjustable welding helmets aren’t recommended because they may not darken quickly enough to protect your eyes. 今年8月12日，一场绚丽壮观的日全食天文奇观将登场，格陵兰岛、冰岛、俄罗斯北部、西班牙和葡萄牙部分地区的数百万民众将有幸目睹这一天象盛事。届时，月球将运行至地球与太阳之间，完全遮蔽太阳的圆面，形成日全食。与此同时，美国北部、加拿大、欧洲大部和非洲西北部地区将能观测到日偏食。 对于期待观赏这一天文盛景的人来说，提前准备一副专用的日食观测眼镜是最重要的安全措施。专家强调，普通太阳镜绝不足以保护眼睛 —— 它们无法用于直视太阳，而合格的日食观测镜的暗度是太阳镜的10万倍，且符合国际安全标准。日食观测镜的镜片通常采用黑色聚合物或含碳颗粒的树脂制成，能够阻挡几乎全部可见光、红外线和紫外线辐射，而普通太阳镜则无法阻隔红外辐射。 美国国家航空航天局指出，只有在日全食的“全食阶段”，也就是月球完全挡住太阳光芒的那短暂瞬间，人们才可以安全地裸眼直视太阳。一旦光线重新显现，就必须立即恢复眼部防护措施。加那利群岛天体物理研究所的专家警告说：“哪怕太阳表面仅剩下1%可见，它所发出的辐射也足以永久损伤眼睛中的感光细胞。” 直视太阳可能导致失明或视力受损。2017年美国日全食期间，一名年轻女性在使用医生认为不符合安全标准的日食眼镜观测日食后，双眼被诊断患上日食性视网膜病变——这是一种因太阳辐射暴露而导致视网膜受损的疾病。目前，日食性视网膜病变尚无治疗方法，病情可能有所改善或恶化，但这是一种永久性的损伤。 那么，如何才能安全地观测日全食呢？ 美国天文学会给出了明确的操作指南：如果你平时佩戴近视镜或老花镜，请保持佩戴，然后将日食观测镜罩在眼镜外面，或者将手持式观测器置于镜片前方。在抬头望向太阳之前，务必先戴好日食观测镜；在移开视线、转过身去之后，再摘下眼镜。同时，家长务必时刻留意佩戴日食眼镜的儿童，确保他们在直视太阳时不会擅自取下眼镜。 NASA特别警告：切勿在佩戴日食观测镜或使用手持式太阳观测器的同时，通过任何未经滤波的光学设备（如相机镜头、望远镜、双筒望远镜）直视太阳。这是因为太阳光线经过光学设备聚焦后，强度极高，足以烧穿观测镜或观测器上的滤光层，进而对眼睛造成严重伤害。 除了专用的日食观测镜，使用电焊滤光片也可以安全地观测日食，因为现行的国际安全标准部分正是借鉴了这类滤光片应用于太阳观测的经验。不过，专家不建议使用自动变暗或可调式电焊面罩，因为这类设备可能无法在瞬间迅速变暗以有效保护眼睛。 (Translated by DeepSeek) | 