Stunning New Image of Milky Way Displays Over 3 Billion Stars

Have you ever looked up into the clear night sky and tried to count the stars? The Dark Energy Camera in Chile was able to do just that and more. Scientists released a survey of a portion of our home Milky Way galaxy that contains 3.32 billion celestial objects, including billions of stars. 

The National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab) operates DECam as part of an observatory project in Chile. The new astronomical dataset is the second release from the Dark Energy Camera Plane Survey (DECaPS2). NOIRLab called it “arguably the largest such catalog compiled to date” in a statement on Wednesday.

For those who want to take a look, NOIRLab’s smaller-resolution version of the survey gives a sweeping overview, while a web viewer offers more detailed data.  

This wide strip of the Milky Way contains billions of celestial objects as part of the  Dark Energy Camera Plane Survey.


The camera used optical and near-infrared wavelengths of light to spot stars, star-forming regions and clouds of gas and dust. “Imagine a group photo of over 3 billion people and every single individual is recognizable,” said Debra Fischer of the NSF. “Astronomers will be poring over this detailed portrait of more than 3 billion stars in the Milky Way for decades to come.” 

The survey looks at the Milky Way’s disk, which appears as a bright band running along the image. It’s packed with stars and dust, making it difficult to distinguish what’s happening. It took careful data processing to sort it all out.

“One of the main reasons for the success of DECaPS2 is that we simply pointed at a region with an extraordinarily high density of stars and were careful about identifying sources that appear nearly on top of each other,” said Harvard University graduate researcher Andrew Saydjari, lead author of a paper on the survey published in The Astrophysical Journal this week.

Though 3 billion stars may sound like a lot, it’s only a small fraction of the estimated 100 billion stars in the Milky Way. The new survey covers just 6.5% of the night sky as seen from the Southern Hemisphere. 

DECaPS2 was an epic, multi-year project consisting of 21,400 individual exposures and 10 terabytes of data. NOIRLab’s description of the survey as a “gargantuan astronomical data tapestry” is fitting. We’ve never seen the Milky Way quite like this before. It’s beautiful and it’s humbling.