Re: [Phys-L] Percent of Sun Covered Duing Eclipse
There's 0% chance that the numbers presented (by reputable sources) for sun
coverage are wrong. The umbra is very sharply defined in a solar eclipse -
so it's not terribly surprising (and I have experienced it myself) that
even if you're in the low 90% range, it still seems reasonably light.
There is so much light scattered in the atmosphere that isn't coming
directly from the sun but reaches your location if you're in the
partial zone that a partial eclipse is fairly unnoticeable until you're in
the upper 90's. My experience in the 2017 eclipse is that it needed to be
quite close to total before it was clear that the sky was darkening
substantially.
Todd
On Tue, Apr 9, 2024 at 9:22 AM Richard Tarara via Phys-l <
phys-l@mail.phys-l.org> wrote:
> We were supposedly to be in the higher 90s percent-wise but saw the
> same---some darkening but nothing very spectacular. Unfortunately, I
> didn't
> have the proper glasses and my pin-hole camera attempt didn't work too well
> either.
>
> Richard W. Tarara
> Professor of Physics, emeritus
> Saint Mary's College
> Notre Dame, Indiana
>
> Free Physics Instructional Software
> Windows and Mac
> sites.saintmarys.edu/~rtarara/software.html
>
> -----Original Message-----
> From: Phys-l <phys-l-bounces@mail.phys-l.org> On Behalf Of dgpolvani---
> via
> Phys-l
> Sent: Monday, April 8, 2024 6:14 PM
> To: Phys-L@Phys-L.org
> Cc: dgpolvani@gmail.com
> Subject: [Phys-L] Percent of Sun Covered Duing Eclipse
>
> Here in Baltimore one of the weather stations announced our partial eclipse
> would be 88% at maximum (3:02 pm EDT). At this time, the sky did grow
> darker, but not as dark as I expected given an 88% eclipse. Was the
> weather
> report wrong, or is the amount of sunlight received by a spot on the earth
> not directly proportional to the amount of the sun's disk visible at that
> spot? I am ignoring secondary effects such as the sun's corona.
>
> Don Polvani retired physicist, engineer
>
>
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--
Todd K. Pedlar
Professor of Physics and Physics Department Head
Luther College, Decorah, IA
pedlto01@luther.edu
(563) 387-1628
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