Globe at Night

Globe at Night
Name	Globe at Night
Type	Citizen-science project
Established	2006
Focus	Light pollution monitoring, astronomy outreach
Country	International

Globe at Night is an international citizen-science campaign that solicits naked-eye measurements of night sky brightness from volunteers to map light pollution across United States, Canada, United Kingdom, Australia, New Zealand, Japan, France, Germany, Mexico, and other countries. The project links amateur observers, educational institutions, and professional researchers to provide long-term datasets used by organizations such as the International Astronomical Union, the National Aeronautics and Space Administration, the European Space Agency, the United Nations Environment Programme, and the Light Pollution Science and Technology Institute. Volunteers include members of Royal Astronomical Society, American Astronomical Society, Royal Society, Smithsonian Institution affiliates, and local astronomy clubs.

Overview

Globe at Night combines public participation with scientific aims to quantify skyglow using simple observation protocols promoted through partners like National Optical-Infrared Astronomy Research Laboratory, Natural History Museum, London, Royal Observatory Greenwich, Jodrell Bank Observatory, and Royal Museums Greenwich. The campaign produces spatially resolved light-pollution maps that complement satellite missions such as Suomi NPP, Landsat, VIIRS, and DMSP Operational Linescan System while informing policy discussions involving International Dark-Sky Association, United Nations Educational, Scientific and Cultural Organization, and municipal planning bodies in cities including New York City, Los Angeles, London, Paris, and Tokyo.

History

Initiated in 2006 by collaborators from institutions such as National Optical-Infrared Astronomy Research Laboratory, Southwest Research Institute, European Southern Observatory, and Asia-Pacific Regional Space Agency Forum, the project drew on prior community science models used by Audubon Society, Royal Society for the Protection of Birds, and Zooniverse. Early pilots engaged networks including Astronomical Society of the Pacific, British Science Association, Canadian Space Agency, and Australian Astronomical Observatory. Subsequent phases integrated data frameworks from programs like Global Forest Watch and standards influenced by Intergovernmental Panel on Climate Change reporting practices. Major campaign years coincided with events such as International Year of Astronomy (2009) and milestones in International Dark-Sky Association advocacy.

Methodology

Participants follow standardized protocols influenced by observational methods from American Association of Variable Star Observers, Royal Astronomical Society of Canada, and educational curricula promoted by Smithsonian Astrophysical Observatory. Observers compare visible constellations—such as Orion, Ursa Major, Scorpius, Cassiopeia—against magnitude charts derived from stellar catalogs like Hipparcos, Tycho-2, Gaia to estimate limiting magnitude. Data submission occurs via web portals and mobile apps developed with input from European Space Agency software teams, using geolocation tied to Global Positioning System, timestamps aligned with Coordinated Universal Time, and metadata that references local municipalities (e.g., San Francisco, Chicago, Berlin, Madrid). Calibration efforts have incorporated photometric cross-checks with instruments used at observatories including Kitt Peak National Observatory, Mauna Kea Observatory, and Paranal Observatory.

Data and Results

Aggregated datasets have been used in comparative studies with satellite radiance products from VIIRS and light-emission inventories maintained by World Bank and European Environment Agency. Peer-reviewed analyses published in journals such as Monthly Notices of the Royal Astronomical Society, Astrophysical Journal, Nature Astronomy, and Science Advances demonstrate correlations between citizen observations and satellite-derived sky brightness over regions including Southeast Asia, Sub-Saharan Africa, Western Europe, and North America. Time-series analyses reveal trends associated with urban growth in metropolitan areas like Delhi, São Paulo, Cairo, and Istanbul and lighting technology transitions in municipalities such as Los Angeles and Barcelona that adopted LED retrofits. Data contributed to environmental assessments prepared for United Nations Environment Programme reports and urban sustainability plans coordinated by the World Health Organization.

Impact and Outreach

Globe at Night influenced public awareness campaigns alongside advocacy by International Dark-Sky Association, educational programs at Hayden Planetarium, Griffith Observatory, and curricula used by National Science Teachers Association and Royal Society of Chemistry outreach. Exhibitions and citizen workshops were held in venues including Smithsonian National Air and Space Museum, Science Museum (London), California Academy of Sciences, and festivals such as World Science Festival and Prague Science Festival. The project informed lighting policy debates in councils of European Union member states and municipal ordinances in cities like Flagstaff, Arizona, which is recognized for dark-sky protection.

Participating Organizations

Notable partners and participants include International Astronomical Union, International Dark-Sky Association, National Aeronautics and Space Administration, European Space Agency, Royal Astronomical Society, American Astronomical Society, Smithsonian Institution, Natural History Museum, London, Australian Astronomical Observatory, Canadian Space Agency, National Optical-Infrared Astronomy Research Laboratory, World Health Organization, and local astronomy clubs affiliated with institutions such as Harvard University, University of Cambridge, University of Oxford, Massachusetts Institute of Technology, University of Tokyo, University of Sydney, and University of Cape Town.

Criticisms and Limitations

Critiques parallel those raised for other citizen-science initiatives like Galaxy Zoo and eBird: variable data quality, uneven geographic coverage favoring urbanized nations (e.g., United States, United Kingdom, Germany), and challenges integrating subjective naked-eye estimates with calibrated radiometric satellite data from VIIRS and Landsat. Methodological limitations have been discussed in publications with contributors from Max Planck Society, Chinese Academy of Sciences, and Indian Institutes of Technology, emphasizing needs for standardized training akin to protocols used by World Meteorological Organization and for addressing biases associated with cloud cover, moon phase, and light-source spectral shifts from sodium to LED technologies.

Category:Citizen science