Superblue

Superblue is a term used to describe a rare astronomical event where a blue moon occurs very close to the autumn equinox. This alignment can lead to a particularly vibrant orange or red hue in the moon's appearance, a phenomenon known as a harvest moon. The term "superblue" itself is a combination of "supermoon," which refers to a full moon that occurs when the Moon is at its closest point to Earth in its elliptical orbit, and "blue moon," which is the second full moon in a single calendar month. While the "blue" in blue moon does not refer to the moon's color, the superblue event can indeed make the moon appear to have a reddish or orangish tint due to atmospheric conditions.

The rarity of a superblue moon stems from the coincidence of several astronomical factors. The lunar cycle, which dictates the timing of full moons, and the Earth's orbital period around the sun, which determines the equinoxes, must align in a specific way. Additionally, the Moon's perigee, its closest orbital point to Earth, must also coincide with these events. When these conditions are met, the full moon appears larger and brighter than usual due to its proximity, and its color can be intensified by the scattering of sunlight through Earth's atmosphere.

The term superblue is not an official astronomical designation but rather a colloquialism that has gained popularity. The visual spectacle of a superblue moon, combining its enlarged appearance and potential for striking coloration, makes it a notable event for skywatchers. While the "blue" aspect of a blue moon is a calendrical designation, the observable color of a superblue moon is a result of the interaction between moonlight and atmospheric particles.