2 thoughts on “Monday’s Eclipse

  1. Stopped by the local library’s “Eclipse party” last Monday (they were handing out free glasses to those who attended the whole program). They also had some guests from NASA presenting (which is why they couldn’t hold the event next Monday).

    Here’s some tips and trivia I picked up:

    Expect emergency-level traffic during the eclipse period, as drivers will likely be more distracted with looking at the sky than the road. A Carolina school district is holding kids for an extra hour to keep them safe from this.

    Valid solar glasses conform to ISO 12312-2 standard
    #14 welder’s glass is an acceptable substitute

    One way to test if your viewer is dark enough is to shine your smartphone’s camera LED through it. If, it isn’t completely blacked out, you can only barely see the light, it should be good enough. Some online sellers were selling counterfeit solar glasses. Amazon is offering refunds.

    If using a telescope or binoculars, sun filters are best at the front end of the optics, not the rear. I saw a picture of melted solar glasses lenses because they put them behind the telescope’s eyepiece.

    Long shipping tubes / poster tubes are better than shoeboxes for making a pinhole viewer out of. The longer length allows for a larger projection. My 3′ tube viewer makes about a 1/4″ sun. 3’x3″ square shipping boxxes can be found at the post office.

    Also at the post office are commemorative color-changing Eclipse-themed Forever stamps. When cold, they show the Sun’s corona around a black moon. When warmed, the moon brightens to show its surface. $7.84 for a single aheet of 16.

    Other non-optical (no lenses) viewers include:

    Poke a pinhole in a paper plate, shine the sun on another plate

    weave your fingers to make one or more small holes, and watch the curved shadows on the ground

    Watch the spots of sun shining through tree leaves

    Sir Isaac Newton did some early experiments with sun viewing. He’d stare at the sun for a period of time, and record how long it would take for his vision to recover. His final test, it took a month.

    NASA couldn’t get more glasses to hand out. The solar viewer company they asked had already ramped up to 24/7 production, making 50k pairs aday, and still they couldn’t keep up with demand.

    If you live in Carbondale, Illinois, you’ll be in totality both for this eclipse, and the next one in 2024

    Helium was discovered by observing the emmission spectra of the Sun’s corona during an eclipse. Scientists also theorized a second new element, coronium, to explain the green. It turned out it wasn’t a new element but plain old Iron… ionized 14 times over.

    Want to help NASA? Download their “GLOBE Observer” app for iOS and Android. Register as a citizen scientist, and use the app and your phone’s thermometer to record how the temperature changes while under the shadow of the eclipse. After the eclipse, you can record measurements on current cloud cover, and soon you can record the presence of local mosquito larva.

    All the “animals will act strange” warning means is they’ll think it’s nighttime for a few minutes. If your pets start speaking in tongues, it’s /probably/ not because of the eclipse.

    In other space news, October 28 is International Observe the Moon Day

  2. Eclipse watching: Looking at totality unmagnified won’t hurt you. (There is argument about the effect of magnified infrared, ie., telescope or binoculars, from the corona at totality.) The danger is staring into the sun at the final crescent while awaiting totality. At that point light is reduced enough that it doesn’t consciously hurt (your head doesn’t reflexively turn away) yet it can burn your retina. I say all this NOT theoretically but from experience. The scars from the the total solar eclipse of March 7, 1970 were visible every time I closed my eyes for about two decades following that event. I suspect that they have now merged into a second “Blind Spot”, although I no longer see the crescents with closed eyes.

    It was worth it.

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