“…Finally the sun disappears altogether and then the moon, shining still more brightly, proudly ascends the throne of the sun.”
On December 3rd, we all witnessed the ‘Full Cold Moon’, the closest and the brightest full moon of 2017. The amazing sky watching event was a treat to the moon-gazers, yet not all were aware of the heralding Supermoon. From time to time, Supermoons make the moon appear a little brighter and closer than normal, although the difference is hard to spot with the naked eye.
What is a Supermoon and how often does it occur?
A Supermoon is a Full Moon or a New Moon that approximately coincides with the closest distance that the Moon reaches to Earth in its elliptical orbit, resulting in a larger-than-usual apparent size of the lunar disk as seen from Earth.
The orbit of the Moon is distinctly elliptical in shape. The non-circular form of the lunar orbit causes variations in the Moon’s angular speed and the apparent size as it moves towards and away from an observer on Earth. The point of the orbit closest to Earth is called Perigee, while the point farthest from the Earth is known as Apogee. Thus, Perigee and Apogee refer to the distance from the Earth to the Moon. A full moon at Perigee can appear 14 percent larger to viewers on Earth. It can also be 30 percent brighter than other Full Moons.
Hence the answer to the above question lies with where the moon is on its orbit of Earth. Generally, Supermoons occur about every 414 days, but that is just an average count. They can occur several times a year.
When is the next Supermoon?
This time, it kicked off a trilogy of consecutive Supermoons: First was on 3rd December 2017, and the next ones will happen on January 3rd and 31st 2018.
If you can catch only one episode of the Supermoon trilogy, catch the third one as it will be extra special. First of fall, the January 31st Supermoon will feature a total lunar eclipse which will be totally viewable from Western Northern America across the Pacific to Eastern Asia. The moon’s orbit around our planet is tilted, so it usually falls above or below the shadow of the Earth. About twice each year, a full moon lines up perfectly with the Earth and the Sun such that the Earth’s shadow totally blocks the Sun’s light which will normally be reflected off the Moon.
The Lunar Eclipse on January 31st will be visible during moonset, falling under the Eastern United States where the Eclipse will be partial. The Moon will lose its brightness and will take on an eerie but faint hue with a normal glow from the scattered sunlight that makes its way through the Earth’s atmosphere. As a result, it will cast a reddish hue because the way the atmosphere bends the light.
Totally eclipsed moons are sometimes called the Blood Moon.
Image showing a Full, Partly Eclipsed and Totally Eclipsed Reddish Moon
On January 31st, the Supermoon will also be the second full Moon of the month. Some people call the second full moon in a month, a Blue Moon; that makes it’s a Super-Blue Moon.
The Supermoons are great opportunities for the people to start looking at the moon, not just once but every chance they have. It’s hard for our eyes to distinguish these small changes in size when the moon is high amidst the vastness of the night sky. But anytime you catch a full moon as it rises or sets, while its suspended low on the horizon beaming through the silhouettes of the trees or buildings, its apparent size might make you do a double take.
And this time with a total eclipse, it will be a royal spectacle indeed: a Super-Blue-Blood Moon. Sometimes the celestial rhythm sync up just right to wow us! So don’t miss this moment, step out into the Moon rise or Moon set and look up for the trilogy of sky watching treats.