Skywatchers in Northern California are in for a treat Sunday evening: a lovely eclipse of the Harvest Moon. Here is the best part, you don’t have to get up at some crazy hour to see it, the Moon will rise just after partial eclipse has begun and the total eclipse, which lasts about an ho
ur, will be visible at 7:11 pm, which is even before my bedtime!
Total lunar eclipses are one of my favorite celestial happenings for a couple of reasons: they happen every few years in clusters (this is the last in a series of four that have been visible in North America) and you don’t need any special equipment to enjoy them – just your warm moist eyeballs (though binoculars or a telescope are fun too). A lunar eclipse, unlike a solar eclipse, is totally safe to watch. So enjoy it!
This eclipse is a cool one since it falls just after the Autumnal Equinox (which was Wed., Sept. 23 at 1:21 am), which makes this the Harvest Moon, a full moon associated with the time of harvesting crops.
It also happens right around the time that the Moon is at perigee – it’s closest point in its orbit around Earth. So this is also a “supermoon” or a moon that is about 14 percent larger than normal. We will also have the “Moon Illusion” at work. The Moon looks larger when it is on or near the horizon since your eyes have objects in the foreground to compare it to. It looks smaller when it is high in the sky, but as the name explains, this is merely an optical illusion.
What you will see when the Moon rises is a roundish dark shadow as the outer cone of shadow from the Earth, or penumbra, is cast upon the Moon. When totality sets in at 7:11, the Moon will turn orange as the light from all of the sunsets and sunrises around the Earth is refracted through our atmosphere and cast upon the Moon. Mid-eclipse is at 7:47 and the end of totality is at 8:23. The partial eclipse phase ends at 9:27.
Here is something interesting to contemplate as you watch the eclipse. What would you see if you were standing on the Moon? An astronaut standing at Tranquility base, next to Neil Armstrong and Buzz Aldrin’s footprints (yes, they are still there and will be for millennia) would see the lower stage of the Lunar Module Eagle bathed in an eerie orange glow. Looking up at the Earth, our world would appear as a jet black disc surrounded by a narrow but beautiful ribbon of orange/red light – the sunrises and sunsets around the globe where, as Jim Morrison put it, “Night divides the day.”
No need to try to run or hide though, just get out and enjoy the Harvest Supermoon eclipse of 2015.