Geminid meteor shower

Geminid meteor shower, 2012 © Mike Lewinski


The Skywatcher's Guide is the Morrison Planetarium's guide to the skies for July through September 2017.

July 3

Earth at aphelion, or farthest from the Sun, at 94.5 million miles (152 million kilometers). This is 3.1 million miles (5 million kilometers) farther away than when Earth was at perihelion, or its closest point to the Sun on January 4. Occurring in the summertime for the northern hemisphere, this shows that the seasons are not the result of Earth's distance from the Sun, but rather due to the angle and duration of sunlight caused by the tilt of the planet's axis of rotation.

July 8

Full Moon rises at sunset against the stars of Sagittarius the Archer. This full Moon was also traditionally known to Native Americans as the "Buck Moon" (Algonquin), the "Crane Moon" (Choctaw), and the "Buffalo Breeding Moon" (Osage).

July 16

Moon at last quarter, rising around 1 am on the border between the constellations Cetus the Sea Monster and Pisces the Fishes.

July 23

New Moon, marking the start of Dhul-Qi'dah, the eleventh month of the Moon-based Islamic calendar when the thin crescent Moon after new is first seen. This sighting will be possible throughout most of the world just after sunset on the evening of the 24th.

July 30

Moon at first quarter, located in the south at sunset, lit from the right-hand side. The large, dark patches visible are the Sea of Serenity, Sea of Tranquility (where Apollo 11 landed nearly a half-century ago), Sea of Fertility, Sea of Nectar, and—sitting disconnected from the rest—the Sea of Crises.

August 7

Full Moon. Native Americans dubbed this the "Women's Moon" (Choctaw), the "Sturgeon Moon" (Algonquin), and the "Blueberry Moon" (Ojibway).

A partial lunar eclipse occurs, but it's not visible from the US (see Notes).

August 12

Peak of the Perseid meteor shower. See Notes for more information about what is usually the best display of meteors in most years.

August 14

Last quarter Moon rises around midnight, just crossing the boundary from Cetus the Sea Monster into Aries the Ram and located high in the south at dawn, lit from the left-hand side.

August 21

New Moon. This new Moon will pass between Earth and the Sun, casting its shadow onto a path that crosses the United States and causing a much-anticipated total solar eclipse for observers along the path. Described further in Notes.

Sighting of the first crescent after this new Moon marks the start of Dhul-Hijjah, the final month of the Moon-based Islamic calendar. This sighting is possible from Central and South America and possibly the American Southwest on August 22, and more easily throughout the rest of the world on the 23rd.

August 29

First quarter Moon, rising at midday and located due south at sunset, illuminated from its right-hand side.

September 6

Full moon. Native American names for September's full Moon include the "Cool Moon" (Cheyenne), the "Moose-Calling Moon" (Micmac), and the "Wild Rice Moon" (Ojibway).

September 12

Occultation of the star Aldebaran by the Moon just before dawn, visible from the western US and Hawai'i (see Notes). We will see the Moon move in front of the star Aldebaran (the eye of Taurus) and hide it from view for 79 minutes. Aldebaran is one of only a few bright stars close enough to the Moon's path across the sky that can be occulted. As seen from San Francisco, it occurs at 4:29 am and ends at 5:48 am. Timings for other cities can be found here.

Later that night (actually, just after midnight and so during the early minutes of the 13th), the last (or third) quarter Moon rises against the stars of Taurus the Bull.

September 19

New moon. Sighting of the first thin crescent after new marks the start of Muharram, the first month of the Moon-based Islamic calendar. This sighting is possible on the 21st.

September 22

Autumnal equinox, or the beginning of the fall season in the northern hemisphere. South of the equator, it's the vernal equinox, or the beginning of spring. More in Notes.

September 27

First quarter Moon rises at midday and is located due south at sunset. As night falls, look just below it for the "teapot" asterism in Sagittarius the Archer.

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Planetarium by Night

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2017 Pocket Almanac

2017 Pocket Almanac

Download the Morrison Planetarium's 2017 Pocket Almanac to stay up-to-date on eclipses, meteor showers, satellite spottings, and more.

2017 Morrison Planetarium pocket almanac