Global High Resolution H-alpha Network

About the Network

  • The global high-resolution H-alpha (656.3 nm) network utilizes facilities at the Big Bear Solar Observatory (BBSO) in California, the Kanzelhöhe Solar Observatory (KSO) in Austria, the Catania Astrophysical Observatory (CAO) in Italy, Meudon and Pic du Midi Observatories in France, the Huairou Solar Observing Station (HSOS) and the Yunnan Astronomical Observatory (YNAO) in China, the Mauna Loa Solar Observatory in Hawaii, and the Uccle Solar Equatorial Table (USET) in Belgium.

  • All these observatories have over 300 sunny days a year, good seeing conditions, adequate observing staffs and well established H-alpha telescope systems.

  • Each of the three stations has a 1K x 1K or 2K x 2K CCD detectors available to monitor the Sun with a spatial resolution of 1 arcsec per pixel. Observations of 1 minute cadence are obtained at each station with higher cadence which can be triggered by automated filament eruption detection.

  • The largest time difference in the network is about 9.4 hours between BBSO and YNAO. The difference between BBSO and KSO is about 8.7 hours and that between YNAO and KSO about 5.9 hours. In summer each station can observe 12 hours on clear days. Therefore, normally there is no night gap in the summer. In winter, when each station is expected to operate 8 hours, the BBSO/YNAO gap will be about 1.6 hours and the BBSO/KSO gab about 0.7 hours. Based on the weather records of the three stations, we anticipate a duty cycle of 70% in summers and of 60% in winters.

  • While single station high-resolution H-alpha observations can perform important research, for the following reasons it is necessary to monitor the Sun round-the-clock:

    • The night gap is a severe problem for single station observations. Many important phenomena (e.g. flares and filament/prominent eruptions) could happen during the night gap.

    • The continuous data set certainly will increase the accuracy of the measurements, like e.g. the solar rotation determined from feature tracking.

    • Round-the-clock observations can follow the evolution of active regions which produce flares. Statistical analysis can enhance our knowledge of flare prediction.

    • Uniformly processed continuous data certainly are desirable by users around the world for correlative studies with both ground-based and space observations.