First quarter moon, Spica, on July 23

Tonight – July 23, 2015 – people around the world will see the moon at or near its first quarter phase, and in the vicinity of the star Spica.

Although the moon and Spica appear close together on the sky’s dome, they are actually nowhere close in space. Tonight’s first quarter moon resides about one and one-third light-seconds distant from Earth while Spica lies far beyond the moon, at about 260 light-years away.

The first quarter moon comes to pass on July 24, at 4:04 Universal Time. Although the first quarter moon happens at the same instant worldwide, the clock reads differently by time zone. At our U.S. time zones, the first quarter moon occurs on July 24, at 12:04 a.m. EDT – but on July 23, at 11:04 p.m. CDT, 10:04 p.m. MDT or 9:04 p.m. PDT.

At first quarter moon, the lunar disk is half-illuminated by sunshine and half-engulfed in the moon’s own shadow. You are seeing one-half of the moon’s daylight side and one-half of the moon’s nighttime side. The lunar terminator – the shadow line dividing the lunar day from the lunar night – shows you where it’s sunrise on the first quarter moon.

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If we could whisk you off to where you could view the moon’s far side, you’d also see the lunar disk half-lit by sunshine and half-engulfed in the moon’s own shadow. However, the lunar terminator on the far side of tonight’s first quarter moon would show you where the sun is setting, rather than rising.

We’ve found over the years that people tend confuse the moon’s far side with its dark side. The moon’s far side – or back side – is the half of the lunar globe that we can’t see from Earth. The dark side is the side that lies opposite the sun. The far side is only the dark side at full moon.

Although the moon has a permanent far side, it has no permanent dark side. Everyplace on the moon gets about two weeks of night followed by two weeks of day.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

The moon will be edging toward the planet Saturn in the evenings ahead. The green line depicts the ecliptic – path of the sun, moon and planets across our sky.

Bottom line: Tonight – July 23, 2015 – enjoy the seeing the first quarter moon near Spica, the brightest star in the constellation Virgo the Maiden.

How much of the moon can we see from Earth?

Donate: Your support means the world to us

from EarthSky http://ift.tt/1M5IsMo

Tonight – July 23, 2015 – people around the world will see the moon at or near its first quarter phase, and in the vicinity of the star Spica.

Although the moon and Spica appear close together on the sky’s dome, they are actually nowhere close in space. Tonight’s first quarter moon resides about one and one-third light-seconds distant from Earth while Spica lies far beyond the moon, at about 260 light-years away.

The first quarter moon comes to pass on July 24, at 4:04 Universal Time. Although the first quarter moon happens at the same instant worldwide, the clock reads differently by time zone. At our U.S. time zones, the first quarter moon occurs on July 24, at 12:04 a.m. EDT – but on July 23, at 11:04 p.m. CDT, 10:04 p.m. MDT or 9:04 p.m. PDT.

At first quarter moon, the lunar disk is half-illuminated by sunshine and half-engulfed in the moon’s own shadow. You are seeing one-half of the moon’s daylight side and one-half of the moon’s nighttime side. The lunar terminator – the shadow line dividing the lunar day from the lunar night – shows you where it’s sunrise on the first quarter moon.

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

If we could whisk you off to where you could view the moon’s far side, you’d also see the lunar disk half-lit by sunshine and half-engulfed in the moon’s own shadow. However, the lunar terminator on the far side of tonight’s first quarter moon would show you where the sun is setting, rather than rising.

We’ve found over the years that people tend confuse the moon’s far side with its dark side. The moon’s far side – or back side – is the half of the lunar globe that we can’t see from Earth. The dark side is the side that lies opposite the sun. The far side is only the dark side at full moon.

Although the moon has a permanent far side, it has no permanent dark side. Everyplace on the moon gets about two weeks of night followed by two weeks of day.

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

The moon will be edging toward the planet Saturn in the evenings ahead. The green line depicts the ecliptic – path of the sun, moon and planets across our sky.

Bottom line: Tonight – July 23, 2015 – enjoy the seeing the first quarter moon near Spica, the brightest star in the constellation Virgo the Maiden.

How much of the moon can we see from Earth?

Donate: Your support means the world to us

from EarthSky http://ift.tt/1M5IsMo