Atmospheric transparency in the optical and near IR range above the   Shatdzhatmaz summit
  The study of atmospheric extinction based on the MASS data has been carried out using the classical photometric pairs method. The extinction in V band can be estimated at 0.m 19. The water vapour content has been derived from GPS measurements. The median value of PWV for clear nights is equal to 7.7 mm. 
Olga Voziakova
astro-ph.IM