The Global Oscillation Network Group (GONG) is a worldwide network of six identical telescopes, designed to have 24/7 observations of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

. The network serves multiple purposes, including the provision of operation data for use in space weather prediction, and the study of solar internal structure and dynamics using

helioseismology Helioseismology is the study of the structure and dynamics of the Sun through its oscillations. These are principally caused by sound waves that are continuously driven and damped by convection near the Sun's surface. It is similar to geoseismol ...

. Deployed in 1995, GONG is a set of six observing systems geographically distributed around the Earth so that the Sun can be observed as continuously as possible. The six observatories are the

Teide Observatory Teide Observatory (), IAU code 954, is an astronomical observatory on Mount Teide at , located on Tenerife, Spain. It has been operated by the Instituto de Astrofísica de Canarias since its inauguration in 1964. It became one of the first major ...

(

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

), th
Learmonth Solar Observatory
(

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

), the Big Bear Solar Observatory (

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

), the Mauna Loa Observatory (

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

), the Udaipur Solar Observatory (

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

) and the Cerro Tololo Inter-American Observatory (

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

). With these sites, GONG typically can observe the Sun 91% of the time, 24/7. GONG was constructed to provide observations for helioseismology, which aims to understand the solar interior by analyzing the sound waves that are trapped in it. In 2001, the original GONG detectors were upgraded to 1000 x 1000 pixels and continuous magnetograms were implemented, and the new system is known as GONG++. While GONG still provides helioseismology data, it now also provides full-disk solar magnetic field maps (magnetograms) every minute and full-disk images of the Sun in the wavelength of the Hydrogen–α (Hα) spectral line every 20 seconds. Thes
data products
are used for research into the solar magnetic field and chromosphere but are also essential inputs into forecasts of space weather. The NOAA Space Weather Prediction Center (SWPC), the US Airforce 557th Weather Wing, and the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

Community Coordinated Modeling Center (CCMC) all use GONG data to predict space weather conditions. GONG magnetograms are used in modeling of magnetic connectivity between the

photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

and the

solar wind The solar wind is a stream of charged particles released from the Sun's outermost atmospheric layer, the Stellar corona, corona. This Plasma (physics), plasma mostly consists of electrons, protons and alpha particles with kinetic energy betwee ...

in support of NASA's

Parker Solar Probe The Parker Solar Probe (PSP; previously Solar Probe, Solar Probe Plus or Solar Probe+) is a NASA space probe launched in 2018 to make observations of the Stellar corona, Sun's outer corona. It used repeated Gravity assist, gravity assists from ...

mission. The GONG Project is managed by the

National Solar Observatory The National Solar Observatory (NSO) is a United States federally funded research and development center to advance the knowledge of the physics of the Sun. NSO studies the Sun both as an astronomical object and as the dominant external influen ...

(NSO) Integrated Synoptic Program (NISP), which is operated by the Association of Universities for Research in Astronomy under a cooperative agreement with the

National Science Foundation The U.S. National Science Foundation (NSF) is an Independent agencies of the United States government#Examples of independent agencies, independent agency of the Federal government of the United States, United States federal government that su ...

(NSF). GONG has been in operation since 1995 and is aging rapidly. To replace it, NSO is proposing to design and build a next-generation Ground-based solar Observing Network, provisionally named ngGONG. In April 2023
NOAA Science Advisory Board
reported on the importance of GONG and its successor data source for space weather operations. It concluded that "GONG provides a vital data source for space weather operations, and it is nearing end of life. The ngGONG project is the most straightforward replacement. It will maintain present operational capabilities, and provide observations for future requirements. The time window to complete ngGONG prior to the demise of GONG is closing." The Board recommended that "NOAA/NWS financially support the design phase for ngGONG, to ensure the initiation of the project." The Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 by the

National Academies of Sciences, Engineering, and Medicine The National Academies of Sciences, Engineering, and Medicine (NASEM), also known as the National Academies, is a Congressional charter, congressionally chartered organization that serves as the collective scientific national academy of the Uni ...

recommends ngGONG as NSF's top priority for its Major Research Equipment and Facilities Construction (MREFC) Program.

Sites

The six GONG stations are located at the geographic coordinates and elevations given in the following table.

Gallery

File:GONG at Learmonth.jpg, GONG shelter in Learmonth, Australia File:Mauna loa clouds.jpg, GONG shelter at Mauna Loa, Hawai'i File:GONG at BBSO.jpg, GONG at Big Bear Solar Observatory, California

External links

GONG info
at the

site

References

{{Reflist Solar observatories