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Due to scheduling and geometry I could only snap last night's lunar eclipse with an older model cell phone on a pedestrian overpass of a brightly lit city street, but surprisingly the Moon was quite bright even during the totality phase (U2 to U3 (14.5 minutes) also see below) when the Moon was within the geometrical umbra of Earth's shadow.

   2021-05-26
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U1 = 09:44:57 UT     first contact with umbra
U2 = 11:11:25 UT     begin totatity
U3 = 11:25:55 UT     end totality
U4 = 12:52:22 UT     last contact with umbra

This eclipse just barely grazed the inside of the umbra.

The last total lunar eclipse I remember was quite a long time ago. It was more central and the Moon barely visible with night adapted eyes viewed from the countryside, so it's not a fair comparison.

But I'd like to ask anyway:

Question: Was the radial gradient of Earth's umbra unusually bright for the May 26, 2021 total lunar eclipse? Might there have been more light scattered from Earth's atmosphere into the umbra than average, due to weather or perhaps the recent eruption Mount Nyiragongo in the Democratic Republic of Congo? Or was the brightness of the northern edge of the Moon pretty much normal for this geometry?


Snap shot of total lunar eclipse at 2021-05-26 11:23:58 UTC

above: Snapshot at 2021-05-26 11:23:58 UTC North is left (altered only to obscure a phone number on a sign)

below: from eclipse.gsfc.nasa.gov's Total Lunar Eclipse of 2021 May 26 found here. North is up

screenshot from Total Lunar Eclipse of 2021 May 26 https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2021May26T.pdf

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Based on your description of your experiences, my guess is that it’s not that this eclipse was especially bright, but rather that the previous one you saw was unusually dark. My experience (late 1990s to present) has always been that a totally eclipsed moon is easy to see even under bright urban conditions, but this page says that there were some eclipses in the 1980s and early 1990s that were hard to see due to recent volcanic eruptions. Do you know the date of the previous eclipse you saw?

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  • $\begingroup$ This is a good point. The one I remember was quite a while ago! 1975-May-25 (by process of elimination form here) $\endgroup$
    – uhoh
    May 29 at 5:24

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