In order to fully appreciate the significance of the evening of Wednesday, Jan. 31, one should have a basic understanding of a number of astronomical phenomenon.
Not one, but four separate lunar events will take place that night for the first time in 150 years. The full moon will not only rise as a blue moon, a supermoon and a blood moon but, will be part of a total lunar eclipse.
The full moon is the lunar phase when the moon appears fully illuminated from Earth’s perspective. This occurs when Earth is located directly between the sun and the moon. A blue moon is the name given to the second full moon in a calendar month. Blue moons happen every two-and-a-half years on average; however, a total eclipse of a blue moon has not happened since 1866.
According to the NASA website, the moon’s distance varies each month between approximately 357,000 and 406,000 kilometers due to its elliptical orbit around the Earth. A full moon at perigee is visually larger by up to 14 per cent in diameter, and shines 30 per cent more light than one at its farthest point, or apogee. The full moon cycle is the period between alignments of the lunar perigee with the sun and the earth, which is about 13.9443 synodic months or 411.8 days. Thus, approximately every 14th full moon will be a supermoon. However, halfway through the cycle, the full moon will be close to apogee, and the new moons immediately before and after can be supermoons. Consequently, there may be as many as three supermoons per full moon cycle. Since 13.9443 differs from 14 by very close to 1⁄18, the supermoons themselves will vary with a period of about 18 full moon cycles (about 251 synodic months or 20.3 years).
In more understandable terms, a supermoon is a full moon or new moon that passes close to the Earth on its elliptical orbit, resulting in the moon appearing larger than normal. Supermoons sometimes coincides with a total lunar eclipse. The most recent occurrence of this was in September of 2015, while the next will not happen until 2033.
A blood moon occurs when a full moon is completely within the dark umbral shadow cast into space by planet Earth and the only sunlight able to reach the moon is red light that has been filtered and refracted by the Earth’s atmosphere.
A lunar eclipse occurs when the moon passes directly behind the Earth into its umbra. This can occur only when the sun, Earth and moon are aligned exactly, or very closely, with the Earth in the middle.
So now, with a basic understanding of terminology, you can hopefully better appreciate just how unique next Wednesday evening’s events will be.
In searching for information to write this column I came across the TimeDate.com website. According to TimeDate.com, the penumbral eclipse will begin to be visible here in the Shuswap at 2:51 a.m. on Wednesday, January 31. By 3:48 the partial eclipse phase will be underway with the moon starting to become red and by 4:51 a.m. the total eclipse will start with a completely red moon. At 5:29 a.m. the eclipse will reach the maximum stage with the moon closest to the centre of the shadow. By 6:07 a.m. the total eclipse will have ended and by 7:11 a.m. the second half of the partial eclipse will also be ended. I’m sure here will be a lot of great photographs on any number of websites afterward.
The long-range weather forecast for the Shuswap area seems to indicate Wednesday, Jan. 31 may or may not be cloudy. Rain is a possibility for earlier in the day, but who knows.
All I know is that regardless of any weather forecast, I will be setting my alarm and will be getting up in the middle of the night in hopes of observing one of the most unique astronomical events of the last 150 years.
On many a night over the years I have looked up at the moon and always felt a sense of wonder.
I have peered at it through binoculars, telescopes and telephoto lenses. I have looked at it as it hovered above prairie landscapes and mountain lakes alike, and come next Wednesday morning, I will once again look up and with a bit of luck will get to witness something pretty darned cool.
*Editor’s note: Originally the column stated the eclipse woudl be visitble at 2:51 a.m in the evening of Jan. 31. It is actually goign to be visible at 2:51 a.m. in the early morning hours of Jan. 31. So prepare for the eclipse and set your alarm before you go to bed on Tuesday, Jan. 30.