| Solar Brightness and Magnetic Discontinuities Collected by the Solar Observing Optical
Network (SOON) |
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This data file consists of solar brightness and magnetic discontinuities collected
by the Solar Observing Optical Network (SOON). SOON consists of up to five US Air
Force Air Weather Service observatories. The Air Force operates five solar telescopes
distributed in longitude to maintain continuous coverage to monitor solar active regions
at optical wavelengths. GDC archives histograms of intensity versus area every minute
for the active regions as well as magnetograms of the magnetic field structure and
tachograms of plasma velocities on an irregular schedule. The basic SOON telescope
is a 25-centimeter evacuated refractor mounted on a polar axis. It has a tunable monochromatic
filter centered on the hydrogen-alpha absorption line (6562.8A) of the solar spectrum.
Shifting the filter characteristics slightly off center from the H-alpha peak results
in pictures of the solar surface region at differing depths. Corresponding to the
optical images of solar regions are the digital "brightness-area" data. These data
are often plotted as brightness-area histograms for a particular time or, in a 3-3-dimensional
display, showing a time sequence of changing intensity of optical emissions from areas
of solar active regions. Each digital scan of a region describes the amount of solar
surface area within a pre-set rectangular viewing grid that is of brightness level
N, where N ranges from 1 to 64 and represents the gray scale range from black to white.
The automatic capability of the SOON telescope system allows the rapid collection
of this brightness-area information on many active regions on the sun. By using these
data, quantitative measures, including instability, growth/decay rates, and precise
areas for each active solar region, can be determined.
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