Safe Observing: Check Your Eclipse Viewers

 

eclipse viewing safely
View the eclipse safely using approved solar shades or viewers. Credit: Courtesy Mark Margolis / Rainbow Symphony

The eclipse is coming! As everybody who has even looked at social media knows, there’s a big star party on Monday, August 21st. True, we’ll only be paying the closest attention to ONE star as it gets eclipsed by the Moon, but for millions of people, it’s the event to see. Not only will we be watching from along the path of totality, but many more will see it via the Web and TV. I’ve posted earlier about eclipse viewing and one thing is paramount: view it safely!  This is so important that I’m posting again about how to view safely and what to use.

A total solar eclipse is about as bright as the full Moon — and just as safe to look at without eye protection (and this is important) ONLY DURING TOTALITY. The Sun is dangerously bright to look at without protection. So, outside of totality, you should view it only through special-purpose “eclipse glasses” or hand-held solar viewers. Do NOT use homemade filters or ordinary sunglasses.

An eclipse is an amazing thing to observe and I encourage everybody who can to get out to a place where you can experience totality. Just be safe as you look at the events unfold overhead. Regardless of where you observe from, however, take precautions. If you have eclipse glasses, check them out using this info from the American Astronomical Society. 

Amazon Issues a Recall

In the past few days, Amazon has issued a recall/refund scheme for eclipse viewers it has found to be unsafe. It appears that some sellers have counterfeited glasses to sell. Others, such as Baader, Thousand Oaks, and Lunt are being lumped into that recall, even though those companies are among the best-known and reputable dealers of solar filters out there. If you ordered from Amazon, you may be okay — you may not be. It’s best to test your glasses and filters before the big day.

Above all, be safe! And enjoy the spectacle!
How to tell if the glasses you have are safe?  So, here’s a quick way to tell: hold them up to a lighted bulb and look at the bulb through them. If you can’t see the bulb, then they are okay to use.  I have tested glasses using both regular light bulbs and LED flashlights, and have seen NO light through them. However, they do let me see the Sun. So, perform this simple test and if your glasses don’t let the light from a bulb through, you should be fine with the Sun. As always, YMMV.

Alternate Eclipse Viewing Methods

If you have any doubt about using eclipse viewers, then use the pinhole projection method. The AAS site outlines how to do it using varying methods. The TL;DR version is: use a pin to prick a hole in a piece of cardboard. Let sunshine stream through the hole onto a piece of white paper or a wall or even the ground. During the eclipse, you will see tiny little eclipsed Suns in the interplay of light and shadow. This is for indirect viewing only. Obviously, don’t look at the Sun through the colandar or cheese grater.

Other folks, such as my friend Martin Ratcliffe, suggest using a colander or a cheese grater. You can also lace your fingers together as a sort of makeshift colander. If there are trees nearby, look at the shadows their leaves cast on the ground during the eclipse.

Above all, be safe! And enjoy the spectacle! If nothing else, check out the online eclipse casts. NASA is hosting one and I imagine every TV station in the country (if not around the world) will be doing the same.

Don’t Discard those Glasses!

Okay, so after the eclipse, those glasses aren’t just junk. For one thing, there will be another eclipse crossing the U.S. in 2024. Until then, you can safely use your viewers to view the Sun and look for sunspots. Make your viewers part of your sky observing toolkit. Just keep them safely stowed away in an envelope or something that will prevent damage to the solar filter material. They should last you for several years, but always do a safety check before using them to view the Sun.

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