Our home is in the Milky Way: a spiral galaxy containing over 300 billion stars that span 100,000 light years. Our galaxy appears to be a creamy pink and white blur from the glare of stars and the limitations of our eyesight. However, an international team of astronomers used the Isaac Newton Telescope (INT) in the Canary Islands to take a closer look and tease that blur apart, accounting for each stellar object individually.
This paper is the product of observations between 2003 and 2012 using the INT/WFC Photometric Hα Survey of the Northern Galactic Plane (IPHAS), and resulted in the most detailed catalog yet of our galaxy, 219 million stars in total. The study was led by Geert Barentsen of the University of Hertfordshire and the results were published in the journal Monthly Notices of the Royal Astronomical Society.
The INT operates on optical wavelengths and its 2.54 meter mirror allows it to collect a tremendous amount of light. It also uses two broad band filters and an H-alpha filter, allowing it to capture deep red wavelengths and create a sharp, detailed image of structures a million times too faint for our eyes to see. This map includes all 219 million known stars, including our sun.
The data were compiled and given an artistic representation with a map showing the density of the galaxy. The highest concentrations of stars are shown in light orange. This image represents just a snippet of the entire galaxy’s disc, though the entire catalog has been made available for free access and includes summaries on each structure. This data can help astronomers understand the structure of our galaxy and account for all of its components.
Image credit: Hywel Farnhill, University of Hertfordshire. View the image larger