What is blue moon?
Actually, the term “Blue moon” has nothing to do with our natural statelite color. This traditional name expresses the uniqueness and rarity of the phenomenon that it denotes.
According to the most definition (also called the monthly definition), the blue moon is the second full moon in a calendar month with two full moons. However, this definition is oversimplified and results from an error. According to the traditional seasonal definition, if there are 4 full moons in one season, the penultimate one takes the name of the blue moon.
Halloween Full Moon,
This year, the observes worldwide are lucky enough to see the blue moon the precisely corresponds to the almanac’s traditional definition. The full blue moon will adorn the sky on October 31, 2020, at 10:49 a.m. EDT ( 14:49GMT), shining in the constellation Aries.
Also, on October 30, the moon reaches it’s apogee, the most distant point from the earth in the lunar orbit, and therefore it might appear smaller than usual.
Opposition of Uranus,
One more bright astronomical event will happen on Halloween: Uranus will reach Opposition on October 31, 2020, at 11:38 a.m EDT ( 15:38).
The ice giant will align with the sun and the earth, while the earth will be between Uranus and the sun. During Opposition, the blue-green planet will shine at a magnitude of 5.7 in the constellation Aries.
Around opposition, Uranus also passes the closet point to the earth, the perigee, and appears at it’s largest and brightest in the sky. Use a telescope to observe Uranus as this ice giant is almost impossible to see with the naked eye.
So, whether you see a blue coloured moon this Halloween or not but you may see blue icy giant Uranus if you have telescope.
Wishing you a spooky Halloween! Enjoy the sky!