The first of two total lunar eclipses this year visible from Tucson will occur conveniently this Sunday evening, May 15 (16 May 2022 UT).
Here are the local circumstances for Tucson, Arizona.
|7:28 p.m.||Partial Eclipse Begins||3°|
|8:29 p.m.||Total Eclipse Begins||14°|
|9:12 p.m.||Greatest Eclipse||21°|
|9:54 p.m.||Total Eclipse Ends||26°|
|10:56 p.m.||Partial Eclipse Ends||33°|
|11:30 p.m.||Penumbra last visible?||35°|
|11:51 p.m.||Penumbral Eclipse Ends||36°|
There are few astronomical events as impressive as a total lunar eclipse, and we’ll have a front-row seat Sunday evening.
Every month, the full moon passes close to the Earth’s shadow, but because of the Moon’s tilted orbit it usually passes above or below the shadow cone of the Earth. This month is different!
Sunday evening, the Moon orbits right through the Earth’s shadow. At 6:32 p.m., the Moon dips his proverbial toe into the Earth’s shadow, when the Moon is still 7˚ below Tucson’s ESE horizon. This is the undetectable beginning of the eclipse, when the leading edge of the eastward orbiting-Moon “sees” a partial solar eclipse. When no part of the Moon sees anything more than the Earth blocking some but not all of the Sun, we call that a penumbral eclipse. The very subtle penumbral shading may just begin to be detectable around 7:00 p.m., but here in Tucson the Moon won’t even rise until six minutes after that.
When the partial eclipse begins at 7:28 p.m., the lower left edge becomes the first part of the Moon to “see” a total solar eclipse. In other words, from part of the Moon now, the Earth totally eclipses the Sun.
Totality begins at 8:29 p.m. when all of the Moon sees the Earth completely blocking the Sun. Mid-totality occurs at 9:12 p.m., when the center of the Moon is closest to the center of the Earth’s shadow. At that moment, the Moon’s color should be darkest.
That color is caused by sunlight refracting (bending) through the Earth’s atmosphere and shining on the Moon even though from the Moon the Earth is completely blocking the disk of the Sun. The reddish or orangish color imparted to the Moon during totality is the combined light of all the world’s sunrises and sunsets. What a beautiful thought! Had the Earth no atmosphere, the Moon would utterly disappear from view during totality—the time it is completely within the Earth’s umbral shadow.
Totality ends at 9:54 p.m., and the partial eclipse ends at 10:56 p.m. As the last vestiges of partial solar eclipse leave the Moon, the (penumbral) eclipse ends at 11:51 p.m.
This leisurely event can be enjoyed with the unaided eye, binoculars, a telescope, or all three. Don’t let anyone in the family miss seeing it!