Sunspot Observation for NearSys Station, 22 September 2017

Only a single sunspot was visible as the sun set behind a cloud bank. The penumbra had a calculated diameter of 11,107 miles and the umbra a diameter of 4,859 miles. Compare this to Earth's diameter of 7,920 miles.

The original image. The sunspot is located near the edge of the 9:00 position.

The image after thresholding.