- The global high-resolution H-alpha (656.3 nm) network
utilizes facilities at the Big Bear Solar Observatory (BBSO) in California, the
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.
- 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.