Umbral Dots Observed in Photometric Images taken with 1.6 m Solar   Telescope
  Umbral dots (UDs) were observed using the 1.6 meter solar telescope. Achieved conventional diffraction limit in the TiO 705.68 nm spectral line used was 0.1". The 418 UDs were analysed. Median diameter was 0.5'' and median intensity difference between darkest part of the UD's background and brightest part of the UDs was 37%. Despite to achieved resolution, no UDs substructures were visible. The analysed UDs appeared to be circular. 
Aleksandra Andic
astro-ph.SR