Alpha. Denotes a unipolar SUNSPOT group. Beta. A sunspot group having both positive and negative mag- netic polarities, with a simple and distinct division between the polarities. Beta-Gamma. A sunspot group that is bipolar but in which no continuous line can be drawn separating spots of opposite polarities. Delta. A complex magnetic configuration of a solar sunspot group consisting of opposite polarity UMBRAe within the same PENUMBRA. Gamma. A complex ACTIVE REGION in which the positive and nega- tive polarities are so irregularly distributed as to prevent classification as a bipolar group.

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