Astronomers have combined data from the USNO-B (US Naval Observatory) and Sloan Digital Sky Survey to painstakingly produce a new catalogue of the universe covering 35% of the northern sky, which includes 44 million stars and galaxies that have been observed at least twice.
The entire catalogue gives a more accurate measurements of an individual star’ brightness than had ever been possible before, and provides a number of important breakthroughs including making it easier to identify which stars brightness has changed over the past few years. Interestingly, Prof Bryan Gaensler from the ARC Centre of Excellence for All-sky Astrophysics in Australia and Dr Greg Madsen from the University of Cambridge, found that about 250,000 objects, or about 0.6% of all the stars in the sky, registered a significant change in their brightness over the span of a human lifetime.
Commenting on the new catalogue, which is to be released on the internet for public access, Prof Gaensler, said: “Thanks to clever computer algorithms, we thankfully didn’t need to inspect all billion stars and galaxies individually. But even so, processing the data and then testing everything to make sure we got it right took us more than a year.
Further commenting on the significance of the catalogue published in The Astrophysical Journal Supplement Series, Prof Gaensler, added: “This catalogue comes at just the right moment for the next generation of telescopes. Using our measurements, astronomers who find interesting new stars in the sky can essentially go back in time, and see what the object they’re studying was doing 60 years earlier.”