Globe at Night 2024

Starts:  Mar 31, 2024 09:00 (UTC-11)
Ends:  Apr 9, 2024 17:00 (UTC-11)

Starts:  March 31, 2024 
Ends:  Apr 9, 2024 
Audience: All Ages
Program Type: Citizen-Science
Program Distribution: International

What is the program about, and how to participate
What would it be like without stars at night? What would we lose? Starry night skies have given us poetry, art, music, and the wonder to explore. A bright night sky affects energy consumption, health, and wildlife.

Globe at Night (GaN) is a rewardingly inclusive way to bring awareness to the public on the disappearance of the starry night sky, its cause, and solutions. GaN encourages citizen-scientists worldwide to record the brightness of the night sky. During ten days per month of moonless evenings, children and adults match the appearance of a specific constellation with 7-star maps of progressively fainter stars found at (Moonless evenings are chosen to avoid having a natural light bulb in the night sky when taking measurements.) People then submit their choice of star map in-situ using the “web app” on a smart device.

The easy steps to participating in the campaign are listed at Resources for finding the campaign constellations and your latitude and longitude, when to observe, how to use the star charts, and how to report are all included. Over 180,000 observations from 180 countries have contributed to a light pollution map in 14 years of the program.

What resources are available

Resources for GaN exist to make participation easy. There are two ways of taking measurements. The online app for data reporting is in 26 languages. On-the-fly mapping enables citizen scientists to see observations immediately. Activity guides for every campaign help with the measurements. Postcards in 21 languages provide a means to advertise. STEM activities for young children and problem-based learning activities for older students were created to experience real-life scenarios: role-playing sea turtles hatching (misdirected by lights onshore) or analyzing an ISS image of Houston to estimate the wasted energy cost and carbon footprint. GaN's Facebook page exists to encourage dialogue and bring cutting-edge news. To entice interest, we had monthly newsletters and serial podcasts starring the Dark Skies Crusader. Stay tuned as the newsletters are coming online again!

What you can do with the data

The open GaN database has many potential uses. Participants can explore the data from the last 16 years using the GaN interactive map. You can see how your area is doing by putting your city's name in the Location Box at the top of the map. Add a radius and tap or click "Search" to see the results. 

Partnering with special programs

We have built a community of practitioners in various ways worldwide and have metrics on behavioral changes. GaN has been part of special campaigns like the National Park Service, the National Geographic BioBlitz, and Tucson in 2011. In 2009 and 2015, GaN was an official citizen-science campaign for the United Nations-sanctioned International Years of Astronomy and Light, respectively, setting record participation. To maintain the community and create new partnerships, we have teamed with SciStarter to track participants via a dashboard. The Girl Scouts and SciStarter in “Think Like a Citizen-Scientist,” and with STARS4ALL’s Light Pollution Initiatives. GaN was rated in the top 10 citizen-science programs of 2017.

An invitation for you to join the team

GaN has provided the public with various ways to be better stewards of lighting more responsibly to minimize the disappearance of our potentially starry night sky. GaN is a flagship program of the National Optical-Infrared Astronomy-Research Laboratory (NSF'S NOIRLab) and is the preeminent US national center for ground-based, nighttime optical and infrared astronomy.

We invite you to participate in GaN this Global Astronomy Month. Your GaN measurements will help make a difference in preserving our night sky heritage.

The Challenge

We are challenging people to take measurements every half mile or kilometer from the center of a town or city to its outskirts and a little beyond. The challenge is to see what the difference is in night sky brightness. For Tucson, an LM 2 has been measured at the city center, and an LM 7 beyond its eastern edge. The difference of 5 means it is 100 times brighter at the city center than at the eastern edge. Once you complete your measurements, email your observer IDs (one per measurement) to us at Those who can complete these measurements in their own town or city will be invited to become Dark Skies Ambassadors. Dark Skies Ambassadors are a part of the Dark Skies for All Global Project for the International Astronomical Union. Details for Dark Skies Ambassadors will be described on the  website.