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Where I am (Vancouver, WA), the Sun will be 99%+ covered. Will I be able to see the "Beads of Baily" when the sun is 99%+ covered in my area ?

Downtown Portland, OR is expected to be 99.4% (according to local news). I expect Vancouver, WA, a suburb just north of downtown Portland, to be over 99% as well (99.3-99.2%??)

ProfRob
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iMerchant
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1 Answers1

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No, at 99% a narrow sliver of sun will be visible, the width of that sliver will be about 1.5% of the diameter of the sun at its thickest point.

Baily's beads are caused by the sun shining through valleys on the edge of the moon. Such a valley would have to be about 50km deep (or surrounded by hills 50km high). You do get some beads at the thin edge of the sliver but these would be too bright to see against the sliver of sun (which would still be blinding bright)

To get Bailey's beads you need totality, with the sun shining through valleys. Baily's which is why they are normally only visible for a few seconds before true totality, usually a couple of seconds after the predicted start of totality.

You can see the worksheet I used to make these estimations at https://ggbm.at/sZ3EYp7z however it is undocumented.

James K
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  • James K, can we assume from your calculations and Geogebra worksheet at https://ggbm.at/sZ3EYp7z that if one is within one-half mile of the totality zone, one can still see Bailey's Beads, but much further than that, and it is very unlikely? I was thinking of watching the April 8th eclipse from 218 Portland St, Lancaster, NH, which is half a mile outside the path of totality. – Peter Orlowski Mar 29 '24 at 15:01
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    Don't do it. Totality is worth the walk! Bailey's beads are not (and anyway you're more likely to see bailey's beads if you are in the path of totality than if you are not. But anyway, this isn't an answer to the question, so expect a mod to clean it up soon. – James K Mar 29 '24 at 15:31
  • @PeterOrlowski You're so close! You really should try to get inside the path of totality. https://physics.stackexchange.com/q/806950/123208 – PM 2Ring Mar 29 '24 at 19:51