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Where’s the moon? Waxing gibbous

Full moon – and a penumbral lunar eclipse – will come on February 11, 2017 at 00:33 UTC. For the Americas, your fullest moon and eclipse are the night of February 10.

Last night’s moon – February 7, 2017 – from La Lune The Moon‘s Patrick Casaert in Meaux, France.

A waxing gibbous moon appears high in the east at sunset. It’s more than half-lighted, but less than full.

That’s another way of saying that a waxing gibbous moon phase falls between a first quarter moon and a full moon. Next full moon comes on February 11, 2017 at 00:33 UTC; translate to your timezone). That’s the evening of February 10 according to clocks in the Americas.

Eclipse coming! Penumbral lunar eclipse February 10-11, 2017

Relative to a new moon – which is more or less between the Earth and sun, located near the sun along our line of sight – a waxing gibbous moon has moved in its orbit so that it’s now relatively far from the sun in our sky.

A waxing gibbous moon rises during the hours between noon and sunset. It sets in the wee hours after midnight.

Point of interest on the February 6, 2017 moon: Sinus Iridum (Bay of Rainbows) surrounded by the Jura Mountains. Photo by Lunar 101-Moon Book in Toronto, Canada.

Another shot of the February 6, 2017 waxing gibbous moon, with Sinus Iridum (Bay of Rainbows) clearly visible, from P. Weeks in Greenville, North Carolina.

People often see a waxing gibbous moon in the afternoon, shortly after moonrise, while it’s ascending in the east as the sun is descending in the west. It’s easy to see a waxing gibbous moon in the daytime because, at this phase of the moon, a large fraction of the moon’s day side is facing our way.

Thus a waxing gibbous moon is more noticeable in the sky than a crescent moon, with only a slim fraction of the lunar day side visible. Also, a waxing gibbous moon is far from the sun on the sky’s dome, so the sun’s glare isn’t hiding it from view.

Any moon that appears more than half lighted but less than full is called a gibbous moon. The word gibbous comes from a root word that means hump-backed. A gibbous moon can also be a waning gibbous, in the week between full moon and last quarter moon.

On February 7, 2017, the moon was moving through an asterism – noticeable pattern of stars – called the Winter Circle. This photo is from Ken Gallagher in Lake Havasu, Arizona, who wrote: “Didn’t think the clouds would clear, but alas, they did. Enough to catch the Winter Circle. Hard to make out Aldebaran and Capella, but they are there.”

As the moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.

Four keys to understanding moon phases

Where’s the moon? Waxing crescent
Where’s the moon? First quarter
Where’s the moon? Waxing gibbous
What’s special about a full moon?
Where’s the moon? Waning gibbous
Where’s the moon? Last quarter
Where’s the moon? Waning crescent
Where’s the moon? New phase

Deborah Byrd

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