This article first appeared in the Steamboat Pilot. By Jimmy Westlake
Steamboat Springs — You have to go back 11 years for the last time that two total lunar eclipses were visible from Colorado in the same calendar year. The second total eclipse of the moon this year happens during the wee morning hours of Oct. 8 when the full Harvest Moon once again slips into the shadow of the Earth.
The moon’s orbit around the Earth is tipped by about 5 degrees, relative to Earth’s orbit around the sun. This slight misalignment prevents an eclipse of the Moon from happening every time there’s a full moon. There are only two brief windows of time each year, six months apart, when the sun, moon and Earth align just right for an eclipse to occur. These are called our “eclipse seasons.”
The eclipse seasons for 2014 fall in April and October. We had a total eclipse of the moon on April 15, during the previous eclipse season, and here we are, six months later, about to have another one. Each year, the eclipse seasons happen about 18 days earlier.
During a total lunar eclipse, the moon turns a beautiful shade of orange-red, glowing like a hot ember pulled from a fire. This is caused by sunlight filtering through Earth’s atmosphere and being stripped of its blue rays before striking the moon.
Someone standing on the moon during the eclipse would see the darkened earth surrounded by a red “ring of fire” — the combined light of every sunrise and sunset on Earth at that moment.
We are currently enjoying a rare “tetrad” of total lunar eclipses, all four of which are observable from right here in Colorado. The previous tetrad happened in the years 2003-04 and the next one won’t occur until 2032-33. The final two total lunar eclipses of the current tetrad will happen next year on April 4 and Sept. 28.
Next week’s lunar eclipse is an early morning event, so get to bed early and plan to rise before the sun. Look for the first dark “bite” out of the moon’s edge to show up at 3:14 a.m. and grow in size until the onset of totality at 4:25 a.m.
This time, totality lasts for only 59 minutes. The sky should turn nice and dark during that time so that you can see stars around the eclipsed moon.
The backdrop for the moon during this eclipse is the fishy constellation of Pisces, just below the Great Square of Pegasus. Totality ends at 5:24 a.m., after which the bright Harvest Moon completely reappears by 6:34 a.m., just 37 minutes before the sun pops up.
For its encore performance, the moon will turn the tables on the sun in two weeks and give us a partial eclipse of the sun.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Alpine Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper and his “Cosmic Moment” radio spots can be heard on local radio station KFMU. Check out Jimmy’s astrophotography website at www.jwestlake.com.