When and When Not to Use Solar Eclipse Glasses — and the Best Pairs to Buy

When You MUST Use Solar Eclipse Glasses

The ONLY time you can safely view the uneclipsed or partially eclipsed Sun is through special-purpose solar filters, such as eclipse glasses that meet the ISO 12312-2 international safety standard. Here's a breakdown of when their use is absolutely essential:

• Any Time the Sun's Disk is Visible: Even a sliver of the Sun's surface is intensely bright and can cause immediate and irreversible retinal damage. Never look directly at the uneclipsed or partially eclipsed sun without solar eclipse glasses.
• During Partial Eclipse Phases: This includes the moments leading up to and following totality (when the Sun is completely blocked). The partial phases are just as dangerous, if not more so, because the brightness is less obvious, lulling viewers into a false sense of security.
• When Using Unfiltered Telescopes or Binoculars: NEVER use a telescope or binoculars to view the Sun without them being equipped with a properly certified solar filter. The concentrated sunlight magnified by these instruments can cause instant blindness, even with eclipse glasses on if the telescope/binoculars aren't filtered as well.

When Solar Eclipse Glasses Are NOT Necessary

There is only one specific instance when solar eclipse glasses are not required: during the brief period of totality in a total solar eclipse. However, knowing precisely when totality begins and ends is critical. Removing your eclipse glasses too early or putting them on too late is extremely dangerous.

• During Totality (Total Solar Eclipse ONLY): Totality is the moment when the Moon completely blocks the Sun's bright face. The sky darkens, and the Sun's corona (its outer atmosphere) becomes visible. It's safe to look at the Sun without eye protection only during this phase. However, this phase is short lived and you must immediately put your solar eclipse glasses back on as soon as the first ray of sunlight reappears.

Warning: It’s essential to reiterate the importance of timing during a total eclipse. The transition from partial eclipse to totality and back is swift. Many resources will give you specific times for totality based on your location.

Choosing the Right Solar Eclipse Glasses

Not all solar eclipse glasses are created equal. It's crucial to buy certified solar viewers from reputable sources to protect your eyes effectively. Here are key features to look for and recommendations on where to buy them:

• ISO 12312-2 Certification: This is the most critical requirement. Make sure your eclipse glasses are labeled with the ISO 12312-2 international safety standard.
• Reputable Vendors: Purchase solar eclipse glasses from established retailers, science museums, planetariums, or reputable online vendors that have been vetted by astronomical organizations. Beware of counterfeit products sold by unknown sources.
• Examine for Damage: Before use, inspect your eclipse glasses for any scratches, tears, or punctures. If damaged, discard them immediately.
• Coverage: The solar viewers should completely cover your eyes and fit snugly to prevent any sunlight from entering around the edges.

Here are some reputable sources and brands to consider (but always double-check for ISO certification before purchasing):

• Rainbow Symphony
• American Paper Optics
• Thousand Oaks Optical

Solar Eclipse Glasses: Comparison Chart

Here's a quick reference chart summarizing key aspects of solar eclipse glasses:

Protecting Your Eyes and Enjoying the Eclipse

Viewing a solar eclipse is an unforgettable experience. By understanding when to use solar eclipse glasses and investing in certified products, you can protect your eyes and safely enjoy this spectacular celestial event. Always prioritize safety and consult reputable sources for the most accurate and up-to-date information about eclipse viewing.