4 mins read 16 Mar 2021

Count the stars with Globe at Night

Across the globe the night sky is becoming flooded with lights from our cities. Join the Globe at Night international citizen-science campaign and submit your star observations to raise awareness of the impact of light pollution.

Light pollution across Australia, the East Coast of Australia and Sydney. The light yellow indicates the highest light pollution intensity. Credit: SkyGuide App

Imagine looking up to the night sky and seeing the Milky Way. A hundred billion stars shining above us, the light of those stars taking thousands, even millions of years to reach us here on Earth. For most of us, this simple joy is no longer there for us to enjoy as the light from our modern world is obscuring our view of the heavens. The night sky our parents and grandparents saw is very different to that of our children. And it is only getting worse.

Globe at Night is an international community/citizen-science campaign to raise awareness of the impact of light pollution. Light pollution is dramatically reducing the ability to see the stars with the naked eye, and has a wider impact on our environment, especially our nocturnal native animals. According to International Astronomical Union (IAU) Dark Skies Ambassador Michael Marlin, 80% of North Americans and Europeans can no longer see the Milky Way due to light pollution. 

The Globe at Night project asks people from across the Northern and Southern hemispheres to look up at the night sky on a monthly basis and record what stars and constellations are visible from their location.  Over the past 14 years, more than 200,000 measurements have been contributed from people across 180 countries. 

The aim for 2021 is to reach, and hopefully exceed, 15,000 data points. With over 4,323 observations already submitted so far this year, it looks to be well on track. 

The data submitted is used to measure light pollution around the globe and will contribute to raising the awareness of light pollution to people, organisations and governments around the world, as well as contributing data towards energy consumption, and increased night light on plants and wildlife.

Look up and join in

Moon rising in the night sky, Western Australia. Credit: Barney Moss/Flickr

During ten days of every month, citizen scientists are asked to look up at the stars and record what you see. Measurements should be taken more than one hour after sunset, but before the moon has risen. Let your eyes adjust to the darkness and then count how many stars you can see and match it up with one of the seven star maps of progressively fainter stars, within the constellation.

With a smart phone, the Globe at Night web app will put in the date, time, location (latitude/longitude) automatically, but you can also enter this information manually using a computer. 

How to hunt for stars

Globe at Night has easy-to-follow steps for anyone to contribute to the project wherever you are in the world.  

  1. When?  Check the submission dates for your part of the world (Southern Hemisphere dates are listed below). 
  2. Use your favourite night sky app on your phone to find the constellation you’ll be reporting on.
  3. Locate the constellation for that month and select the magnitude chart that best represents the faintest stars visible in that constellation. You can input directly into the Globe at Night report page if you have a smart phone.
  4. Record sky (weather) conditions.
  5. Record any optional star quality data.
  6. Submit.

The Milky Way Arch over Siding Springs - a dark sky location in Australia. Credit: Ángel R. López-Sánchez.

Southern hemisphere constellations and dates

March 5 – 14, 2021   Orion, Canis Major

April 3 – 12, 2021   Crux

May 2 – 11, 2021    Crux

June 1 – 10, 2021   Crux

June 30 – July 9, 2021   Scorpius

July 30 – August 8, 2021   Scorpius

August 29 – September 7, 2021   Sagittarius

September 27 – October 6, 2021   Sagittarius

October 27 – November 5, 2021   Grus

November 25 – December 4, 2021   Grus

Check out the Northern Hemisphere dates and constellations.

Who are Globe at Night?

Globe at Night is a program of National Science Foundation’s NOIRLab, the US national centre for ground-based, night-time optical and infrared astronomy.

GLOBE at Night was developed in 2005 by the National Optical Astronomy Observatory (NOAO) educational outreach group in Tucson (Arizona) in partnership with Global Learning and Observations to Benefit the Environment (GLOBE) and the Environmental Systems Research Institute Inc. Over the past 15 years, Globe at Night has grown from a prototype project in Arizona and Chile to a global cornerstone program.

Find out more about Globe at Night