Skywatchers across much of the world will have the chance to see the moon glowing with an eerie red pallor during a pre-Halloween total lunar eclipse next week.
The “blood moon” total lunar eclipse will rise during the full moon of Oct. 8 just before sunrise in North America, but red might not be the only color people see during the total eclipse. Weather permitting, it’s possible that some sharp-eyed observers might be able to see some blue in the moon’s glow. The event will be the second of four consecutive total lunar eclipses in 2014 and 2015, according to NASA officials.
The Hawaiian Islands are well-placed for both of the total lunar eclipses of 2014. As with the eclipse of April 14-15, we will see this entire October 6-8 eclipse from the islands, weather permitting,
The viewing of the lunar eclipse will run from 11:14 p.m. on October 7 to 2:34 a.m. on October 8. 14 in the Hawaiian Islands; the total phase, when the moon turns very dark and possibly blood red, will run from 12:21 a.m. to 1:24 a.m. early on October 8.
This eclipse actually starts at 10:15 p.m. on October 7, HST; however, for the first hour or so, you will see no change in the full moon’s appearance. This will be the penumbral phrase, as the moon starts to move into the outer shadow, or penumbra, of the earth.
At 11:14 p.m. HST the partial phase of the lunar eclipse will begin. During the partial phase, the moon begins to cross into the deep inner shadow of the earth, or the umbra. For the next hour or so, you will see a deeper and deeper ‘bite’ taken out of the moon as more and more of the moon slides into the earth’s deep inner shadow. Depending on weather conditions, the darkened part of the moon could look reddish or black.
By 12:25 a.m. on October 8 HST the total phase of the eclipse begins. At this point the entire moon is in the earth’s dark inner shadow. The moon will be very dark at this point; sometimes it turns a deep red, sometimes it seems to vanish entirely. The total phase will last over 75 minutes. The total phase ends at 1:24 a.m. on October 8, HST as the moon starts to move out of the earth’s dark shadow.
There will be another partial phase after this total phase ends, and it will last from 1:24 to 2:34 a.m. HST early on October 8 as more and more of the moon returns to ‘normal.’ By 2:34 a.m. the visible eclipse will be over. Though the moon will continue to pass through the earth’s outer shadow, or penumbra, from 2:34 pm till 3:33 a.m., the penumbral phase is of academic interest only and the moon will look like a normal full moon during that whole phase.
The western half of the continental US will get a good view of this October 7-8 lunar eclipse, as well Japan, eastern Australia, and all of Polynesia including New Zealand.
On the East Coast of the United States, totality starts at 6:25 a.m. EDT, but stargazers on the West Coast of the United States will have an even better chance of seeing the rusty glow of the moon during totality. The eclipse will occur between 3:25 a.m. PDT and 4:24 a.m. PDT Wednesday. Observers in Australia and countries along the Pacific Ocean will also have the chance to see the eclipse. [Video: October’s Lunar Eclipse Won’t Be Unusually Dark]
“It promises to be a stunning sight, even from the most light-polluted cities,” NASA eclipse expert Fred Espenak said in a statement. “I encourage everyone, especially families with curious children, to go out and enjoy the event.”
Next week’s eclipse is the second in a so-called total lunar eclipse tetrad, a series of four consecutive eclipses that began earlier this year. The first total eclipse tetrad occured in April. The next total eclipse in the series will occur on April 4, 2015, and the fourth eclipse will rise on Sept. 28, 2015.
During total lunar eclipses, the moon passes into Earth’s shadow, causing the planet to darken the face of the moon, according to NASA. Instead of making the moon go completely dark, the moon shines with a rosy hue during a total eclipse because it reflects light from the sun coming through Earth’s atmosphere.
The color of the moon during a lunar eclipse actually depends on Earth’s atmosphere. For example, a lot of volcanic activity on the planet can pollute the atmosphere and make the moon seem very dark in color during an eclipse, according to NASA.
“Despite some recent eruptions that look spectacular from the ground, there have been no large injections of volcanic gases into the stratosphere,” atmospheric scientist Richard Keen of the University of Colorado said in the same statement. “In the absence of volcanic effects, I expect a rather normal reddish-orange lunar eclipse similar in appearance to last April’s eclipse.”
Red isn’t necessarily the only color skywatchers see during a lunar eclipse. Some observers have claimed to catch a hint of turquoise in the moon’s color as well. The sun hitting the upper stratosphere, Keen said, can explain this odd color contrast.
“During a lunar eclipse, most of the light illuminating the moon passes through the stratosphere, where it is reddened by scattering,” Keen said. “However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer.”
The blue color — which can sometimes be seen on the rim of Earth’s shadow against the moon — is best observed through a small telescope or binoculars during the first and last moments of totality, Keen added.
Lunar eclipses only fall on full moons and usually occur about twice a year. The moon’s orbit is somewhat off-kilter, so instead of getting an eclipse every month, observers on Earth only see a lunar eclipse when the planet’s shadow is favorably aligned with the natural satellite’s orbit.