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All you need to know: September equinox

2017’s September equinox arrives on the 22nd. Happy autumn (or spring)!

Sun over Earth’s equator at equinox

At this equinox, the midday sun will be straight overhead seen from Earth’s equator. It’ll be crossing the equator, moving from north to south.

Hazy light pyramid in east? False dawn

If you’re in the Northern Hemisphere, you can see the zodiacal light, or false dawn, at this time of year. If you’re in the Southern Hemisphere, look for it after sunset.

Moon and the Twins next few mornings

Enjoy the moon and Gemini stars, Castor and Pollux, Friday and Saturday mornings. These 2 stars aren’t really twins, but they’re noticeably bright and close together on the sky’s dome.

Farthest lunar perigee on September 13

The moon reaches perigee – its closest point to Earth – once each month. Today’s perigee is the most distant one of 2017.

Use Great Square to find Andromeda galaxy

Today’s sky chart shows you how to star-hop to the Andromeda galaxy – the large spiral galaxy next-door to our Milky Way – from the Great Square of Pegasus.

Use Cassiopeia to find Andromeda galaxy

Many use the constellation Cassiopedia – which is easy to find, shaped like an M or W – as a jumping off point for locating the near-nearest large galaxy to our Milky Way.

How to see the Great Square of Pegasus

It’s easy! The Great Square of Pegasus consists of 4 stars of nearly equal brightness in a large square pattern. Once you find it, you can star-hop to other well-known sights in the sky.

How to see Cassiopeia the Queen

One of the easiest constellations to identify. She’s considered a Queen, but she still sometimes suffers the indignity of being upside-down.

Delta Cephei is a famous variable star

Delta Cephei doubles in brightness every 5.36 days and thereby helped establish the known distance scale of our galaxy and universe.

Moon and Uranus in Pisces September 8

The waning gibbous moon and Uranus, 7th planet outward from the sun, float in front of the delicate constellation Pisces the Fishes on September 8.

Daytime moon, west after sunrise

Although we’re past full moon now, the moon is still big and bright. Also, watch each morning in the west for a pale daytime moon floating against a blue sky.

How Earth looks from outer space

If you were looking with the eye alone, how far away in space would our planet Earth still be visible?

Orion’s Belt points to dazzling Sirius

It’s one of the neatest tricks in all the heavens. Orion’s Belt points to Sirius, the brightest star in the sky.

Before dawn, Orion the Hunter

By early September, the constellation Orion rises in the hours after midnight and is well up by dawn. It’ll continue to rise earlier … and earlier.

Capricornus? Here’s your constellation

No matter where you live worldwide, Capricornus the Sea-goat climbs highest in the sky in early September. How to see it, and how a sea-goat came to reside among the stars.

Alpha Cephei is a rapidly rotating star

While not one of the most conspicuous stars in the night sky, Alderamin – aka Alpha Cephei – is easy to spot, and is interesting for its rapid rotation on its axis.

Closest far-moon of 2017 on August 30

Today’s moon reaches its most distant point from Earth for the month. Astronomers call this point an “apogee” of the moon. This month’s apogee is closer than any other in 2017.

Orion and Sirius the Dog Star

You’ll always know it’s the sky’s brightest star, Sirius, if the very noticeable 3 stars in Orion’s Belt point to it.

Look toward our galaxy’s center

On the night of August 26, a waxing crescent moon will set in early evening. So you’ll have dark time to find the Teapot asterism and let it guide you to our Milky Way’s center.