title: The Global Oscillation Network Group (GONG) Project
abstract: Helioseismology requires nearly continuous observations of the oscillations of the solar surface for long periods of time in order to obtain precise measurements of the sun's normal modes of oscillation. The GONG project acquires velocity images from a network of six identical instruments distributed around the world. The GONG network began full operation in October 1995. It has achieved a duty cycle of 89 percent and reduced the magnitude of spectral artifacts by a factor of 280 in power, compared with single-site observations. The instrumental noise is less than the observed solar background.
authors.affiliation: J. W. Harvey, F. Hill, R. P. Hubbard, J. R. Kennedy, J. W. Leibacher, and J. A. Pintar are with the National Solar Observatory, National Optical Astronomy Observatories, Post Office Box 26732, Tucson, AZ 85726-6732, USA. P. A. Gilman is with the High Altitude Observatory, National Center for Atmospheric Research, Post Office Box 3000, Boulder, CO 80307, USA. R. W. Noyes is with the Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA. A. M. Title is with the Lockheed Solar and Astrophysics Laboratory, Palo Alto, CA 94304, USA. J. Toomre is with JILA, University of Colorado, Boulder, CO 80309, USA. R. K. Ulrich is with the Department of Physics and Astronomy, University of California, Los Angeles, CA 90024, USA. A. Bhatnagar is with the Udaipur Solar Observatory, Physical Research Laboratory, Udaipur, India. J. A. Kennewell is with the Learmonth Solar Observatory, IPS Radio and Space Services, Exmouth, Western Australia, Australia. W. Marquette is with the Big Bear Solar Observatory, Big Bear City, CA 92314, and California Institute of Technology, 264-33, Pasadena, CA 91125, USA. J. Patron is with the Observatorio del Teide, Instituto Astrofisica de Canarias, La Laguna, Tenerife, Spain. O. Saa is with the Cerro Tololo Interamerican Observatory, National Optical Astronomy Observatories, La Serena, Chile. E. Yasukawa is with the Mauna Loa Solar Observatory, Hilo, HI 96720, and High Altitude Observatory, National Center for Atmospheric Research, Post Office Box 3000, Boulder, CO 80307, USA.
authors.initials: JW
authors.lastname: Harvey
authors.initials: F
authors.lastname: Hill
authors.initials: RP
authors.lastname: Hubbard
authors.initials: JR
authors.lastname: Kennedy
authors.initials: JW
authors.lastname: Leibacher
authors.initials: JA
authors.lastname: Pintar
authors.initials: PA
authors.lastname: Gilman
authors.initials: RW
authors.lastname: Noyes
authors.initials: AM
authors.lastname: Title
authors.initials: J
authors.lastname: Toomre
authors.initials: RK
authors.lastname: Ulrich
authors.initials: A
authors.lastname: Bhatnagar
authors.initials: JA
authors.lastname: Kennewell
authors.initials: W
authors.lastname: Marquette
authors.initials: J
authors.lastname: Patron
authors.initials: O
authors.lastname: Saa
authors.initials: E
authors.lastname: Yasukawa