A new survey of the Milky Way has been released containing more than 3 billion objects, making it one of the largest astronomical catalogs ever produced. The second data release of the Dark Energy Camera Plane Survey, or DECaPS2, focuses on the galactic plane, which is the view looking across the disk of the galaxy in which most of the stars are located and covers 6.5% of the night sky.
The dataset is available to astronomers to use in their research, but it’s also available for the public to view online in a web browser. The Legacy Survey Viewer shows a variety of different survey images — you can select DECaPS2 images in the box in the top right to view the new data, and zoom in and out using the slider in the top left.
The galactic plane is difficult to image because there are so many stars, which can overlap when seen from Earth, and because there is a lot of dust, which you can see as the dark swirls in the image above and which can obscure stars behind it. So the survey looked in near-infrared wavelengths which can peer through the dust for a better view, to build up a 3D view of the galaxy.
“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 lead author of a paper about the survey, Andrew Saydjari of the Center for Astrophysics | Harvard & Smithsonian, in a statement. “Doing so allowed us to produce the largest such catalog ever from a single camera, in terms of the number of objects observed.”
The total number of objects visible in the dataset numbers 3.32 billion, and is the result of 10 terabytes of data from 21,400 individual exposures taken using the Dark Energy Camera in Chile.
“This is quite a technical feat. Imagine a group photo of over three billion people and every single individual is recognizable!” said Debra Fischer of the National Science Foundation, which funded the Dark Energy Camera. “Astronomers will be poring over this detailed portrait of more than three billion stars in the Milky Way for decades to come. This is a fantastic example of what partnerships across federal agencies can achieve.”
