On Wednesday, January 31, 2018, a rare sight occurred in the night sky. It was what NASA called a trifecta event: a Super Blue Blood Moon and a total lunar eclipse. While this seems like a lot of descriptive words, each actually corresponds to a specific lunar event. The culmination of all four is a spectacular event not seen in the sky in more than 150 years. To break it down, four different moon phenomena occurred that night at once.

First, the moon was a Supermoon. This means the moon was a full moon and also it reached its closest approach to Earth in its orbit. As the moon orbits the Earth, it does not make a perfectly circular path that remains the same distance from the Earth. As it orbits the Earth, it makes different paths due to different gravitational forces working against the moon. During some rotations/orbits, it will get closer than other times. This event makes the moon look larger than normal; it can appear from 14-30% larger and brighter.

While the Supermoon is fairly common, the next element is less so: the blue moon. The phrase “once in a blue moon” originates from this event because a blue moon is when a full moon occurs for the second time in a month. Blue moons occur every 2.7 years because the moon becomes a full moon about every 29.5 days, so every now and then, a year will have 13 full moons rather than the typical 12. While the moon does not actually turn blue, unless there is an external force present like fog or smoke, it is just a name to signify an extra full moon.

The last two aspects are interrelated because this time, the blood moon is caused by the lunar eclipse. The total lunar eclipse occurs when the Earth comes perfectly between the Sun and the moon, they all lineup. When this happens the Earth blocks the Sun’s light that lights up the moon. As light passes through the Earth’s atmosphere the blue light is dispelled and the only light to reach the moon is the red light., hence the reddish hue.

This process is called Rayleigh scattering, and it is what causes the colorful sunsets and sunrises on Earth. It is just the process of light passing through our atmosphere, and in this case, it causes a yellow, orange, or red glow on the moon. This event can occur without a total lunar eclipse, but the fact that the lunar eclipse is causing the blood moon makes this event that much more spectacular.

The culmination of all four events at once led to a spectacular show in the night sky. One of the best places to see the event was the Pacific Northwest, or at least it would have been if we were not in the middle of our overcast/cloudy season. Wednesday, January 31, 2018, I attempted to capture images of the event, and while I was unable to see the total lunar eclipse I was able to capture images of the Super Blue moon, although the blue part is more for labeling.

Below are some of my photos of the Super Moon as seen in Eugene, Oregon on Wednesday, January 31, 2018, around 9:30 p.m.