Skygazers in the western United States will get a special autumn treat when the full moon rises Sunday, Sept. 27. For the first time in 33 years, a “supermoon” combined with a lunar eclipse will grace the early evening sky, making the moon glow red and appear slightly bigger.
An unusual combination of planetary events will be behind the display, said Washington State University astronomer Michael Allen: “The moon’s dusky red color will probably be what appears most unique about it to the naked eye. The color should be impressive.”
Known informally as a blood moon, the reddish hue is caused when most sunlight is blocked from hitting the moon’s surface as the moon passes through the earth’s shadow during a total lunar eclipse.