Sunday, September 27, 2015

A Supermoon Lunar Eclipse!

Sunday, September 27, 2015
6:03 pm

Credit: NASA

We've all heard of supermoons... after all, we've had three of them this year. The same goes for lunar eclipses... we had one this past April. They are both fascinating events.

But what if you were to combine the largest supermoon of the year with a total lunar eclipse?

I had known about this for several weeks, but realized the true scope of the supermoon last night as I was heading towards a gig with my funk band up in the University District. As I walked along the Ave, I noticed a massive moon up in the sky. I could not ever remember seeing a bigger and brighter moon. It turns out that it is going to be even bigger tonight, and blood-red as well. 

Credit: Courtney Seligman

Lunar eclipses happen when the Earth is positioned in front of the sun such that it blocks the moon from receiving direct sunlight. Instead, the moon is positioned in the "umbra" of the Earth, meaning is fully shadowed from the sun. However, it doesn't appear black (and hence invisible) because light from the sun scatters off the Earth's atmosphere and hits the moon, giving it a reddish tint.

"Supermoons" occur because the moon has an elliptical orbit, meaning that it is closer to the Earth at some times during its 27-day orbit than others. When one of these close points corresponds with a full moon, you get a supermoon!

To get both of these occurring at once is exceedingly rare. The last supermoon lunar eclipse occurred in 1982, and the next one will occur in 2033. So enjoy tonight!

Luckily for us, the viewing conditions for tonight will be absolutely perfect. The air quality is great, the air is relatively dry, and there are no clouds in the sky to muck up viewing of this historical event. The model picture below measures outgoing longwave (infrared) radiation and simulates an infrared satellite image. As you can see, there are NO clouds over our region. Pretty awesome!

Valid 08:00 pm PDT, Sun 27 Sep 2015 - 15hr Fcst: Retrieved from UW Modeling Website

The partial eclipse is now underway, and the total eclipse will be here within a half hour. We're lucky... if the eclipse was a little sooner, it would still be light out and would not be nearly as stunning. The times below are in Greenwich Mean Time, so just subtract 8 hours to get PDT. For example, the full lunar eclipse starts at 7:11 pm and ends at 8:23 pm.


Enjoy this unique phenomenon, and take some pictures! I know I will!


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