European Helio- and Asteroseismology Network (HELAS)

    Local Helioseismology Network Activity








    Sunspot Classification Definitions

    Date: day.month.year

    L0: Heliographic longitude of the central point of the solar disk.

    B0: Heliographic latitude of the central point of the observed solar disk.

    HG_LONG: The heliographic longitude of the temporal mid-point, central pixel of the data.

    HG_LAT: The heliographic latitude of the temporal mid-point, central pixel of the data.

    R1: The average radius of the umbra - penumbra boundary.

    R2: The average radius of the outer penumbra.

    Duty Cycle: The percentage of 'good' data in time.

    Location: Sunspot group location, in heliographic degrees latitude and degrees east or west from central meridian, rotated to 2400 UTC.

    Magnetic Type: Magnetic classification of the group.

    alpha - unipolar sunspot group.
    beta - sunspot group having both positive and negative magnetic polarities (bipolar), with a simple and distinct division between the polarities.
    beta-gamma - sunspot group that is bipolar but which is sufficiently complex that no single, continuous line can be drawn between spots of opposite polarities.

    Z: Modified Zurich-Macintosh Classification.

    D - An elongated bipolar sunspot group with penumbra on both ends of the group.

    Area : Total corrected area of the group in millionths of the solar hemisphere.

    LL : Longitudinal extent of the group in heliographic degrees.

    NN : The number of visible sunspots on the Solar disk.

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