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First quarter moon midway between supermoon and micro-moon

January-8-first-quarter-moon

Tonight for February 25, 2015

Above: Day and night sides of the January 2014 first quarter moon via Earth and Moon Viewer

This first quarter moon comes about one week after the new supermoon on January 1 and one week before the full micro-moon on January 15-16. In other words, tonight’s moon is halfway between the nearest new moon and farthest full moon of 2014.

Click here for a definition of supermoon.

Click here for a definition of micro-moon.

The January 1 new moon enjoyed supermoon status because the new moon closely aligned with lunar perigee – the moon’s nearest point to Earth in its orbit for the month of January. In fact, this January 1 new moon was the closest new moon of 2014 … but not the closest moon overall. That distinction will go to the full moon of August, 2014.

In January 2014, the new moon aligns with perigee on January 1 and 30, whereas the full moon coincides with apogee on January 16.  The Earth swings to perihelion - its closest point to the sun for the year - on January 4, 2014. Image credit: NASA. For illustrative purposes, the Earth's eccentric - oblong - orbit is greatly exaggerated. Earth's orbit is nearly circular.

In January 2014, the new moon aligns with perigee on January 1 and 30, whereas the full moon coincides with apogee on January 16. The Earth swings to perihelion – its closest point to the sun for the year – on January 4, 2014. Image credit: NASA. For illustrative purposes, the Earth’s eccentric – oblong – orbit is greatly exaggerated. Earth’s orbit is nearly circular.

Some two weeks after the January 1 new moon, on the night of June 15-16, some will call the full moon a micro-moon. That full moon will closely coincide with lunar apogee – the moon’s farthest point from Earth in its monthly orbit. In fact, the January 15-16 micro-moon will be the most distant full moon of 2014.

The January 2014 first quarter moon lies nearly 25,000 kilometers (15,000 miles) farther away than the new moon supermoon of January 1.

Yet, tonight’s first quarter moon is also about this distance closer to us than the full moon (micro-moon) of January 16.

Perhaps it should come as little surprise that this first quarter moon resides at about the moon’s mean distance from Earth, which is 384,400 kilometers or 238,855 miles away.

Last quarter Earth as seen from the moon at the precise instant of the first quarter moon (2014 January 8 at 3:39 Universal Time). Image credit: Earth and Moon Viewer

Last quarter Earth as seen from the moon at the precise instant of the first quarter moon (2014 January 8 at 3:39 Universal Time). Image via Earth and Moon Viewer

The first quarter moon falls on January 8 at 3:39 UTC. Here in North America, that means the moon reaches its first quarter phase on January 7 at precisely 10:39 p.m. EST, 9:39 p.m. CST, 8:39 p.m. MST or 7:39 p.m. PST.

From everywhere worldwide, the moon shines in front of the constellation Pisces the Fishes. Tonight’s moon lights up the nighttime until late evening January 7, or until after midnight January 8. Depending on where you live, the moon may – or may not – be above your horizon at the exact instant of first quarter moon. But all of us, around the world, will see tonight’s moon as half-illuminated, more or less.

Bottom line: Enjoy the moon tonight, as the half-lit first quarter moon showcases the happy medium between the nearest new moon and farthest full moon of 2014!

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