With 7 meteor showers and the closest approach of Mars, October 2020 was one of the most exciting months. On average, one meteor shower peaked every 4 days. This extraordinary month will an extraordinary ending. This year’s Halloween is going to be special. On 31 October, two celestial events will take place: the opposition of Uranus and a rare Halloween Blue Moon. So here are three important things to know:
1. What’s An Opposition?
In celestial mechanics, a planetary opposition occurs when the Earth lies between the Sun and the planet with Earth being on the same side of the planet as shown below.
During opposition, the planet lies opposite the Sun. Hence, it rises around the sunset, reaches the highest point in the sky around midnight, and sets at dawn. This is the best time to observe a planet. At its opposition, a planet almost reaches its perigee (closest point to the Earth) and appears the biggest and brightest.
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2. How Close Will Be Uranus?
The average distance of Uranus from the Earth is about 19.19 AU (1 AU = 150 million Km, the mean distance between Earth and Sun). At the opposition, the planet will be at 18.79 AU. This means the gas giant will be 60 million Km closer to the Earth than its average distance.
3. How To Watch This Event?
When a planet is at opposition, it is visible throughout the night. This happens because when Uranus lies opposite the Sun in the sky, the solar system is lined up so that Uranus, the Earth, and the Sun form a straight line with the Earth in the middle, on the same side of the Sun as Uranus.
The planet will make its closest approach exactly at 15:38 GMT on October 31. It will be well placed for observation, in the constellation Aries. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time. Uranus will have an apparent magnitude of +5.8 so it won’t be visible with the unaided eye. You’ll need a telescope for that.
A Rare Event On October 31
Though Uranus is only visible in a telescope, October 31 won’t disappoint you. It’s a Blue Moon on Halloween after 76 years. The last time the Blue Moon was spotted on Halloween day, that is, October 31, was in the year 1944.
According to a report in CNET, in a rare treat, the 2020 Halloween full moon will be visible to the entire world, rather than just parts of it, for the first time since World War II.
A Blue Moon is the second full moon in a calendar month. Usually, months have only one full moon, but occasionally a second one sneaks in. Full moons are separated by 29 days, while most months are 30 or 31 days long; so it is possible to fit two full moons in a single month. This happens every two and a half years, on average. Fun Fact: Every Full Moon on Halloween is a Blue Moon!