Globe at Night

Globe at Night is an international citizen-science campaign to raise public awareness of the impact of light pollution by inviting citizen-scientists to measure & submit their night sky brightness observations.

Can you find Leo?

Once you have found Leo, you will be able to see why the ancients visualized this asterism as a lion and you will find it very easy to spot in the night sky. However, if you have never had anyone point out this constellation, looking for Leo can be very much like trying to spot a lion hiding in the grasslands of the African Savannah. Much like any time you are looking for something new, it is usually easier to start with something you already know. In the case of the night sky, one of the most recognizable constellations is that of the Big Dipper. Look for it in the North. You can trace it’s curved handle to the four stars that make up the bowl of the dipper. The two stars that delineate the far side of the bowl are often called pointer stars. If you follow them to the North, they point right at the North Star (Polaris), which also happens to be the first star in the handle of the Little Dipper. Following the pointer stars to the South will point you right to Leo. Another way to think about using the Big Dipper to find Leo is to think about poking holes in the bottom of the dipper. The water that falls through the holes rains on Leo. So now you know where to start looking, but you need to know what to look for. The pointer stars of the Big Dipper point to the head of Leo, which is made up of stars the form an arc or backward question mark. The “dot” of the question mark is Regulus, the brightest star in the asterism. Regulus means “little king” – fitting for the constellation Leo, and is actually a double star system that can be viewed with binoculars. Regulus and the second brightest star in the backward question mark form a trapezoid with two other stars of similar brightness nearby. The brighter of the two other stars is Denebola, which means “tail of the lion,” another fitting name, as it marks Leo’s tail.

Visible in: Northern hemisphere

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Can you find Bootes?

To find Bootes, look for the Big Dipper constellation in the north. Follow the arc made by the Dipper's handle until you see a bright star. This is Arcturus, which is located in what would be the waist of Bootes. The rest of the stars in Bootes form the shape of a kite, with dimmer stars beneath the diamond shape of the kite forming his legs.

Visible in: Northern hemisphere

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Can you find Crux?

The constellation Crux (also known as the asterism of the Southern Cross) is easily visible from the southern hemisphere at practically any time of year. For locations south of 34°S, Crux is circumpolar and thus always visible in the night sky. It is also visible near the horizon from tropical latitudes of the northern hemisphere for a few hours every night during the northern winter and spring. Crux is bordered by the constellations Centaurus (the Centaur), which surrounds it on three sides, and Musca (the Fly). Centaurus is one of the brightest and largest constellations in the southern sky. The two brightest stars in Centaurus, Alpha and Beta Centauri, are often referred to as the “Southern Pointers” or just “The Pointers”, allowing people to easily find the constellation of Crux. (Alpha Centauri is also the 4th brightest star in the night sky.) Crux is sometimes confused with the nearby False Cross by stargazers. Crux is somewhat kite-shaped, and it has a fifth star (α Crucis). The False Cross is also diamond-shaped, somewhat dimmer on average, does not have a fifth star and lacks the two prominent Pointer stars.

Visible in: Southern hemisphere

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Join us for the May, 2025 campaign!

We are off to a great start this year with 6741 observations so far! Help us reach our goal of 20000 data points for 2025!

Check out the dates and constellations

6741

Observations from 2025

20000

Goal for 2025

313649

Total Observations

How to report data?

Practice finding all the Globe at Night Constellations, when you are done practicing follow the 6 steps:

Go Outside

During the campaign dates, go outside more than an hour after sunset (8-10 pm local time). The Moon should not be up. Let your eyes become used to the dark for 10 minutes before your first observation.

Use App

Use a night sky app on your phone outside to find the constellation from where you are.

Open Form

Go to the Globe at Night Report page to start to enter Globe at Night measurements. Make sure you are in “Nighttime version”

Fill your location

With a smart phone, the app will put in the date, time, location (latitude/longitude) automatically. Otherwise please type them in. For your location, type the street address closest to your observation along with the city, state or province and country.

Choose the star chart

Choose the star chart that looks most closely to what you see toward your constellation. That is, what is the faintest star you can see in the sky and find in the chart?