SOUTHERN UTAH – Skywatchers who get up early Saturday morning, or stay up late Friday night, will have a chance to witness the simplest and most widely shared of sky shows – a total lunar eclipse.
An eclipse of the moon happens when the moon moves into the shadow of the earth and grows dark. This can happen only at full moon, when the moon is opposite the sun in the sky.
Usually the moon’s orbit takes the moon above or below the earth’s shadow, but if the alignment is just right, the moon can move into and through the shadow. The moon grows dark as sunlight that would fall on it is blocked by the Earth, the St. George Astronomy Group said in a press statement.
The moon darkens and turns a reddish color when in the earth’s shadow, but it doesn’t disappear.
Sunlight refracted around the edge of the earth and through the earth’s atmosphere falls on the moon. This refracted sunlight is reddened for the same reason that sunsets are often red – red wavelengths of light penetrate the atmosphere better than other wavelengths.
According to Earthsky.org, the term “blood moon” is used to describe the reddish hue of a full lunar eclipse, which happens because the sun’s rays pass through the Earth’s atmosphere.
Sky-watchers will have a second chance to witness the moon turn red on the evening of Sept. 27, when another total lunar eclipse will cross the Americas, Europe and Africa.
Saturday’s lunar eclipse is the third in a series of four lunar eclipses that occur in a row — known in astronomical terms as a “tetrad.”
The two previous eclipses in the tetrad occurred April 15 and Oct. 8 2014; the fourth and final eclipse will occur Sept. 27.
The eclipse officially begins at 3:01 a.m. MDT on Saturday morning when the moon’s left edge begins to move into the outer part, or penumbra, of the earths’ shadow.
However, the moon won’t begin to darken noticeably until after 4 a.m. By 5 a.m., the darkening will be obvious to the casual observer.
At 5:58 a.m. the moon moves fully into the inner part, or umbra, of the earth’s shadow and totality begins. Totality lasts only 5 minutes and ends at 6:03 a.m., when the moon begins to move out of the central part of the earth’s shadow and brighten once again. By then, the sky will already be quite bright with the approaching dawn.
“This time around, (the eclipse) is going to be really, really good at around four in the morning, said Leesa Ricci, of the Southern Utah Space Foundation.
People can view the eclipse at the Ashcroft Observatory at Southern Utah University, Ricci said.
“That is a pretty good sized telescope … so probably that is the best place to go,” she said.
Although the eclipse won’t peak until 6 a.m., viewing will begin around 4:30 a.m.
Because of the early hour, the St. George Astronomy Group said they will not hold a public observing session to view this eclipse.
No special equipment is needed to see a lunar eclipse, although binoculars or a small telescope will enhance the experience.
During the eclipse, the moon will be very low in the western sky, at an altitude of only 15 degrees, so find a place with a clear view to the west, according to the St. George Astronomy Group.
While watching the moon, pause to notice the bright star Spica 10 degrees to the left of the moon, or about the width of your fist held at arm’s length. The star Arcturus can be seen well above the moon. Farther to the left is the red star Antares, and above and to the right of Antares is the planet Saturn.
- Partial umbral eclipse begins: 4:16 a.m. MDT
- Total eclipse begins: 5:58 a.m. MDT
- Greatest eclipse: 6 a.m. MDT
- Total eclipse ends: 6:03 a.m. MDT
- Partial umbral eclipse ends: 7:45 a.m. MDT
- Moon sets before end of partial umbral eclipse
- St. George Astronomy Group is welcoming new members, see their website
- Ashcroft Observatory website
- National Geographic – Sky Events Web page
- Partial solar eclipse steals afternoon sky; safety tips, viewing locations, where to buy glasses
- Creeping into the shadow, ‘Blood moon’ total lunar eclipse
- Rare ‘Blood Moon’ eclipse shines on Southern Utah; STGnews Photo Gallery
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