05/20/2021 – Ephemeris – Our first look at next Wednesday’s lunar eclipse

This is Bob Moler with Ephemeris for Thursday, May 20th. Today the Sun will be up for 15 hours and 1 minute, setting at 9:10, and it will rise tomorrow at 6:08. The Moon, 1 day past first quarter, will set at 3:51 tomorrow morning.

Next Wednesday’s lunar eclipse will be total as seen from half the Earth’s surface, but not the half we’re on. We will catch the start of the eclipse as the Moon is setting, and the Sun is rising. That puts us in a unique position. For 5 minutes between sunrise and moonset we will be able to see both the Sun and the Earth’s shadow falling on the Moon. The Earth’s atmosphere bends the Sun’s red rays into the Earth’s shadow, which is why the Moon usually appears red when totally eclipsed and not completely black. The Sun’s light rays that pass over our heads will continue through our atmosphere to be bent more and will pass into the Earth’s shadow so someone farther west of us can enjoy the red totally eclipsed Moon.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

This is a diagram of the Moon’s passage through the Earth’s shadow. P1 is the contact with the edge of the Moon entering the Earth’s penumbra shadow, an event that cannot be seen. U1 is the first contact with the Earth’s inner umbra shadow and the start of the partial eclipse. U2 is the second contact with the edge of the umbra and the start of totality. U3 is the third contact with the umbra and the end of totality and the beginning of the ending partial phase. U4 is the end of the partial phase, with the Moon now back in the penumbra. P4 is when the Moon leaves the penumbra. Click on the image to enlarge. Credit: NASA/GSFC/Fred Espenak.

Visibility map for the May 26, 2021. The events U1-4 and P1&4 are contacts with the Earth’s shadow. Click on the image to enlarge. Credit: NASA/GSFC/Fred Espenak.

The two charts above are contained in a single PDF here-> https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2021May26T.pdf.

UT (Universal Time) to EDT conversion: Subtract 4 hours.