The Clearest Photo of a Sunspot Ever Taken

Dynamics in Sunspot Umbra as Seen in New Solar Telescope and Interface Region Imaging Spectrograph Data
by Vasyl Yurchyshyn, Valentyna Abramenko, Ali Kilcik
The Astrophysical Journal, Volume 798, Number 2 (Jan 10, 2015), doi:10.1088/0004-637X/798/2/136 (http://arxiv.org/abs/1411.0192)