- The global high-resolution H-alpha (656.3 nm) network
utilizes facilities at the
Solar Observatory (BBSO) in California, the
Kanzelhöhe Solar Observatory (KSO) in Austria, the
Astrophysical Observatory (CAO) in Italy,
Pic du Midi
Observatories in France, the
Observing Station (HSOS) and the
Astronomical Observatory (YNAO) in China, the
Mauna Loa Solar Observatory in Hawaii, and the
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
- 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
- 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
- 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
- Uniformly processed continuous data certainly are
desirable by users around the world for correlative
studies with both ground-based and space observations.