Almost a Century of “Imaging” Clouds Over the Whole-Sky Dome
Abstract Meteorological whole-sky photography can be traced back to just after the turn of the century. Capturing an objective and well-determined view of the cloud cover over the whole-sky dome has been one of the principal goals of subsequent developments. Three types of photographic systems have been devised: refracting, reflecting, and moving film systems. A moving film apparatus seems to have been the first to capture a whole-sky view, but the technology has not advanced far since then. Reflecting systems are the cheapest for do-it-yourself enthusiasts, but refracting systems are readily purchased. The problem of selecting the most useful method for projection of the sky onto the film has arisen many times in the last 70 yr. Although an equidistant projection system makes relative distance determination easier, cloud amount can be most readily determined from a photograph produced by an equal-area projection system. If such a system is not used, the grid superimposed on the image must correct for are...