![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2016\/09\/esa_s_star_mapper_visualisation\/16128926-1-eng-GB\/ESA_s_Star_Mapper_visualisation_small.jpg\")
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\nIn 1989, ESA launched the first space mission dedicated to astrometry \u2013 the science of charting the sky. The satellite was named Hipparcos<\/a>, echoing the name of ancient Greek astronomer, Hipparchus, who compiled the oldest known stellar catalogue in the second century BC.\n<\/p>\n \nHipparcos operated for over three years and a catalogue based on its data, released in 1997, had a major impact on many areas of astronomy research.\n<\/p>\n \nThis catalogue listed 117 955 stars, reporting their positions with unprecedented accuracy, alongside estimates of their distance from us and motions through the Galaxy. It was a huge advance on the best catalogues compiled from ground-based observations, which contained information for just over 8000 stars.\n<\/p>\n \nThe newly launched ESA Star Mapper<\/a> visualisation is an exploration of some central aspects of astrometric star catalogues, using data from ESA\u2019s Hipparcos mission.\n<\/p>\n \nThis interactive experience allows users to delve into this famous dataset, exploring the three-dimensional distribution of almost 60 000 stars from the Hipparcos Catalogue. Stars are visualised as a function of their brightness; it is also possible to show their colours, as well as names and parent constellations for the brightest stars.\n<\/p>\n \nUsers can get a sense of where in the sky stars were located in the past \u2013 or will be in the future \u2013 based on their motions measured by Hipparcos.\n<\/p>\n \nA visualisation of the \u2018Hertzsprung-Russell diagram\u2019, a tool used by astronomers to study the evolution of stars, is provided as well.\n<\/p>\n \nThe next great breakthrough in this field will come with ESA\u2019s Gaia<\/a> mission, launched in 2013. Gaia will make a census of more than a billion stars \u2013 roughly 1% of the content of our Galaxy \u2013 of such superb precision and detail that it will revolutionise astronomy again.\n<\/p>\n \nThe journey starts at: http:\/\/sci.esa.int\/star_mapper\/<\/a>\n<\/p>\n \nMore about Hipparcos: http:\/\/sci.esa.int\/hipparcos\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" \nIn 1989, ESA launched the first space mission dedicated to astrometry – the science of charting the sky. The satellite was named Hipparcos<\/a>, echoing the name of ancient Greek astronomer, Hipparchus, who compiled the oldest known stellar catalogue in the second century BC.\n<\/p>\n \nHipparcos operated for over three years and a catalogue based on its data, released in 1997, had a major impact on many areas of astronomy research.\n<\/p>\n \nThis catalogue listed 117 955 stars, reporting their positions with unprecedented accuracy, alongside estimates of their distance from us and motions through the Galaxy. It was a huge advance on the best catalogues compiled from ground-based observations, which contained information for just over 8000 stars.\n<\/p>\n \nThe newly launched ESA Star Mapper<\/a> visualisation is an exploration of some central aspects of astrometric star catalogues, using data from ESA’s Hipparcos mission.\n<\/p>\n \nThis interactive experience allows users to delve into this famous dataset, exploring the three-dimensional distribution of almost 60 000 stars from the Hipparcos Catalogue. Stars are visualised as a function of their brightness; it is also possible to show their colours, as well as names and parent constellations for the brightest stars.\n<\/p>\n \nUsers can get a sense of where in the sky stars were located in the past – or will be in the future – based on their motions measured by Hipparcos.\n<\/p>\n \nA visualisation of the ‘Hertzsprung-Russell diagram’, a tool used by astronomers to study the evolution of stars, is provided as well.\n<\/p>\n \nThe next great breakthrough in this field will come with ESA’s Gaia<\/a> mission, launched in 2013. Gaia will make a census of more than a billion stars – roughly 1% of the content of our Galaxy – of such superb precision and detail that it will revolutionise astronomy again.\n<\/p>\n \nThe journey starts at: http:\/\/sci.esa.int\/star_mapper\/<\/a>\n<\/p>\n<\/p>\n