Tonight, the night sky will be dominated by the May full moon, traditionally known as the “Flower Moon.” As the Northern Hemisphere enters its peak spring season, this lunar event marks a period of abundant blooming, lending the moon its poetic name.
A “Micromoon” in the Sky
While the moon will appear fully illuminated, it won’t be at its largest. Because the moon follows an elliptical (oval-shaped) orbit rather than a perfect circle, its distance from Earth varies throughout the month.
Tonight, the moon is near its apogee —its most distant point from Earth. This phenomenon results in what astronomers call a “micromoon.”
– Size Difference: Instead of its average size of 31 arcminutes, the moon will span approximately 29.72 arcminutes.
– Visual Impact: To the naked eye, the moon may appear slightly smaller and more distant than usual.
Viewing Tips: Colors and Constellations
To get the best view, observers should head outside shortly after sunset. As the moon rises low on the southeastern horizon, it may take on a distinctive yellow or orange hue. This is caused by Rayleigh scattering, the same process that creates red sunsets; the moon’s light must pass through the thickest part of Earth’s atmosphere, which filters out shorter blue wavelengths and leaves behind warmer tones.
What else to look for:
As you watch the moon, several celestial landmarks will be visible:
* Bright Stars: Look for Spica and Arcturus (the third brightest star in the sky) shining above the lunar glow. Note that the moon’s brightness may wash out fainter stars in the constellation Libra.
* Planetary Neighbors: On the western horizon at sunset, Venus will appear exceptionally bright, with Jupiter hanging just above it.
* Gemini: Higher in the sky, the stars Castor and Pollux will be prominent in the constellation Gemini.
Looking Ahead: The “Blue Moon”
Tonight’s event is just the beginning of a busy lunar month. On May 31, we will witness a second full moon, commonly referred to as a “Blue Moon.”
This occurs because the lunar cycle (roughly 29.5 days) is slightly shorter than most calendar months. Every few years, these cycles align to allow for 13 full moons in a single year, resulting in two full moons falling within one month.
Note on terminology: Despite the name, a “Blue Moon” does not actually change the color of the moon; it is simply a chronological label for the second full moon in a month or the third of four full moons in a single season.
Summary: Tonight’s “Flower Moon” will be a “micromoon,” appearing slightly smaller due to its distance from Earth, and it sets the stage for a rare second full moon—a Blue Moon—on May 31.
