Panoramic portrait of the Milky Way captures over 3 billion stars

How many stars can you count when looking up clear night sky? Not as much as the Dark Energy Camera in Chile. Scientists have published a survey of part of our galaxy, the Milky Way, which contains 3.32 billion celestial objects, including billions of stars.

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

Casual viewers can enjoy the smaller resolution version of NOIRLab’s survey which provides a comprehensive overview. For those who like to dive into the details, this web viewer lets you dig deeper into the data.

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 each individual is recognizable,” said NSF’s Debra Fischer. “Astronomers will ponder this detailed portrait of more than 3 billion stars in the Milky Way for decades to come.”

The investigation focuses on the disk of the Milky Way, which appears as a bright band along the image. It is filled with stars and dust. There are so many of the two that it can be difficult to know what is going on. The stars overlap. The dust hides the stars. 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 to a region with extraordinarily high star density and were careful to identify sources that appear almost on top of each other,” said said Harvard University graduate researcher Andrew Saydjari. lead author of a paper on the investigation published in The Astrophysical Journal this week.

Several billion stars may seem like a crazy number, but that’s just a small drop in the galactic bucket. NASA estimates that there are at least 100 billion stars in the Milky Way. The new survey only covers 6.5% of the night sky as seen from the Southern Hemisphere.

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