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Solar Brightness and Magnetic Discontinuities Collected by the Solar Observing Optical Network (SOON)
browse graphic 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.