Period Measurement of the Umbral Oscillation in the Sunspot NOAA10593

Umbral oscillations are a type of fundamental phenomena occurring in sunspots. Accurate measurement of umbral oscillation period is important to the understanding of the structure and evolution of sunspots. A high-quality observation of the sunspot within the active region AR10593 was carried out by the spacecraft HINDOE in May 1, 2007 at the Ca II line. By using the Fast Furiour Transformation (FFT), we derive the oscillation period of the sunspot to be about 154s, which means the umbral oscillation in the Ca II line formation region is a typical 3min oscillation.