Early Saturday morning, a total lunar eclipse will grace the sky over Alaska, turning the moon a red-orange color for a few fleeting minutes.
The entire eclipse -- lasting roughly 3.5 hours -- will be visible in most of Alaska. In eastern Alaska and the Southeast panhandle, the moon will set while the eclipse is ending.
During a lunar eclipse, the Earth casts a shadow over the moon as the planet comes between the moon and sun. During the total phase of the eclipse, the entire moon passes through Earth's shadow, and for five to 12 minutes, the moon is likely to appear reddish-orange -- a so-called "blood moon."
The color is caused by sunrises and sunsets around the Earth's rim.The red light refracts through the atmosphere and into the Earth's shadow, which then appears on the moon.
Saturday's total eclipse phase will last only a few minutes because the moon will barely pass through Earth's inner shadow. The upper-right edge of the moon will be brighter than the rest.
Saturday's eclipse will be the second of four lunar and solar eclipses in 2015 and is the one with best visibility in Alaska. It's the third in a series of four lunar eclipses; the second was Oct. 8, 2014, and the last will occur Sept. 28.
Alaskans' ability to see the eclipse is, of course, dependent on local weather conditions. The weather service writes on its Facebook page that "many from the Chukchi coast, to the western Interior and Southcentral Alaska will have a mostly clear sky during (the eclipse's) totality." Partly cloudy to mostly cloudy conditions are forecast for some of the state; check your local forecast for conditions in your area.
This map shows where the moon rises and sets during different stages of the total lunar eclipse on April 4, 2015. In most of Alaska, the entire eclipse will be visible. Illustration courtesy Sky & Telescope
When to see the eclipse
At 1:35 a.m. Alaska Daylight Time, a slight darkening of the moon will be visible as it moves into the Earth's outer shadow (penumbra).
At 2:15 a.m., the partial eclipse begins. That's when the moon enters the Earth's inner shadow (umbra).
At 3:54 a.m., the total eclipse begins. The moon will be fully shaded by the Earth's umbra and will likely turn a reddish-orange color. The total eclipse will last five to 12 minutes, according to the National Weather Service.
At 5:45 a.m., the partial eclipse ends.
At 6:25 a.m., the moon will move out of the Earth's penumbra and will appear fully bright again.