Anyone who has peered into the summer night sky, far from the big city, has probably been amazed at how many stars there are. The task of counting and cataloguing them seems like an impossible task, but generations of astronomers working under the PAN-STARRS, Sloan, DESI and Gaia programs have long been trying to solve this task, publishing periodically new maps, large datasets and images with stunningly high resolution.
Such developments include the recent publication of the largest dataset ever, which includes data on 3.32 billion stars in our galaxy, the Milky Way galaxy. And the end result is simply a gigantic image that can be zoomed in and out literally to staggering limits.
This data set is the result of the Dark Energy Camera Plane Survey (DECaPS2), which observes the disk of the Milky Way in the optical and near-infrared. The Dark Energy Camera is mounted on the Victor M. Blanco Telescope in Chile, at 2,200 meters above sea level, giving the telescope one of the best observation points for the southern hemisphere night sky.
The first DECaPS dataset was published in 2017. The second dataset, DECaPS2, which is approximately 10 TB in size and is compiled from 21,400 images, contains information on 3.32 billion space objects. The combination of the first and second datasets covers 6.5 percent of the entire night sky, which is 13,000 times the area of the full moon.
The disk of our galaxy is quite bright, and the light scattered by huge clouds of cosmic gas and dust sometimes makes it difficult to detect and identify individual stars and other space objects. However, these clouds are not an obstacle in the infrared, and new methods and data processing algorithms that calculate the background behind the star make it possible to recognize individual stars hidden in the depths of nebulae or that are part of dense clusters.
The data set collected from the Dark Energy Camera observations will be used by astronomical scientists for at least the next ten years, and it will form the basis for a large number of new discoveries. And anyone who wants to feel tiny and insignificant against the scale of the universe can view the DECaPS2 image at this address.