by William J. Bechaver
This week, we are being treated to an extraordinary total lunar eclipse.
Total lunar eclipses are not common, so viewing one is always a special occurrence, and an astronomical event of note.
A total lunar eclipse, though not as rare as a solar eclipse such as we experienced in August, occurs when the Earth passes directly between the Sun and the Moon. More accurately, the Moon passes directly through the shadow of the Earth, passing out of the direct sunlight that usually illuminates it, becoming obscured in the shade cast by our planet.
Not as rare as a total solar eclipse, a lunar eclipse is visible to a greater number of people on the planet at one time. A solar eclipse’s path of totality is only a fine path across the surface of the planet, but a lunar eclipse lasts for a longer period of time, and is viewable to anyone who can see the Moon in the sky when it lies within the shadow of the Earth.
This month’s event will be seen, in part or totality, by more than half the people in the world, from North America, to peoples of the Pacific, in Asia and Australia.
Though not as rare, none in history has been as exceptional and unordinary as the one that we will experience this month. And for a number of unusual reasons.
First of all, the mass media will make a priority of pointing out that the full moon of this eclipse will be the closest full moon of the year, making it a popularly touted “super moon”, the largest full moon of 2018.
But in reality, this is the least amazing feature of this month’s event.
Even more rare, is the fact that this eclipse will occur during the second full moon of the month. A full moon occurs every 29 days, with a few hour’s difference. So to have two full moons in one month is not common.
And to have a total eclipse during that second full moon is a extremely rare event indeed. The second full moon of a month has recently been known as a “blue moon”, and to have a blue moon total eclipse is one of the rarest events of all.
But even that is not the most extraordinary fact of this event.
The second full moon coming on the very last day of January makes not only the event that day amazing, but sets up an even rarer event for next month. But let’s get to that a bit later, after covering the details of the amazing total eclipse.
The total eclipse will begin late in the night. In fact, it is early in the morning of Wednesday 31 January. It is so late, in fact, that we will not be able to witness the entire eclipse event.
The Moon will begin to dive into the Earth’s shadow just before five o’clock Wednesday morning, for those of us here in Southern Colorado and Northern New Mexico. By five, you should be able to notice a distinct bite out of the edge of the Moon.
Go out and find the Moon as it is beginning to sink in the west. Periodically watch, as it quickly disappears, becoming completely obscured during the next hour.
The Earth’s shadow will quickly crawl across the surface of the Moon, completely blotting it out when it enters totality about an hour later, at 5:52 a.m. The Moon will appear as a great copper penny in the western sky, the red hue being caused by the sunlight passing through the Earth’s atmosphere.
Totality will last for 76 minutes. The sky will be lightening by the time totality ends, the Sun rising in the east and the Moon sinking in the west, just as it emerges from the edge of the Earth’s shadow.
The remainder of the emergence will occur after the Moon has set for us viewing from here. The amount of totality you will see depends on the clearness of your western horizon, and how level it is.
We will have a second total lunar eclipse in just a few months, at the end of July. Two eclipses so close together are also rare, since we haven’t had one since the one back in September of 2015.
Now, about the rarest occurrence of the year. Not only does January have two full moon’s this year, but the month of February has only 28 days, and no full moon at all—during the entire month!
February is the only month that can occur without a full moon at all, and this year’s rarest occurrence is only possible because there are two in January, the second occurring on the last day of January, leaving February with no full moon during the month at all!
How rare is that? We will do the research and cover that, and the upcoming events next week.
But for this week, and this extraordinary month of January, get out there next Wednesday morning, and see a total lunar eclipse that occurs during the second full moon in a single month.
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• · William J. Bechaver is the director of SPACE • Spanish Peaks Amateur Cosmos Enthusiasts, the premier Astronomical Society for Southern Colorado and Northern New Mexico.