On the night of April 14-15, the moon turned to blood- or at least reddish as a total lunar eclispe occurred. This photograph was taken in Los Angeles, near the LACMA museum’s Urban Light installation. This is the first eclipse of the Tetrad, a quadruple set of eclipses that will occur during the next 18 months.
During a total lunar eclipse, the face of the Moon turns sunset-red for up to an hour or more as the eclipse slowly unfolds. Usually, lunar eclipses come in no particular order. A partial can be followed by a total, followed by a penumbral, and so on. Anything goes. Occasionally, though, the sequence is more orderly. When four consecutive lunar eclipses are all total, the series is called a tetrad. During the 21st century, there are 8 sets of tetrads; however, during the three hundred year interval from 1600 to 1900, there were no tetrads at all.
But why does the moon become a red blood moon? A quick trip to the Moon provides the answer: Imagine yourself standing on a dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down, completely hiding the sun behind it. The eclipse is underway. You might expect Earth seen in this way to be utterly dark, but it’s not. The rim of the planet is on fire! As you scan your eye around Earth’s circumference, you’re seeing every sunrise and every sunset in the world, all of them, all at once. This incredible light beams into the heart of Earth’s shadow, filling it with a coppery glow and transforming the Moon into a great red orb.
To the right of the photograph is the star Spica, the 15th brightest star in the night sky, (well, techinically, its a binary pair of stars).
The name Spica derives from Latin spīca virginis “Virgo’s ear of grain” (usually wheat). In Chinese astronomy, the star is known as Jiao Xiu 1 (角宿一). In Hindu astronomy, Spica corresponds to the Nakshatra Chitra. The 17th century German astronomer Bayer and others referred to the star as Arista. Classical names include Azimech, from Arabic السماك الأعزل al-simāk al-a‘zal ‘the Undefended’, and Alarph, Arabic for ‘the Grape Gatherer’. Other names for the star include Sumbalet, Sombalet, Sembalet Eleandri, Shibbōleth, Citrā, Sa-Sha-Shirū, Kió & Repā.