dew shield

A dew shield is a device used to prevent moisture or condensation buildup on the lens of a camera or telescope collector during night observations.{{cite web|url=http://www.skyandtelescope.com/astronomy-resources/dealing-with-dew/|title=Dew Shields|publisher=skyandtelescope.com|accessdate=November 20, 2017}} The dew shield either shades the lens or provides a small amount of warm air directly in front of the lens or collector to prevent dew from collecting on the element. Some dew shields work by using a heating element that keeps the objective lens warm enough to keep the dew from collecting.{{cite web|url=https://www.astronomics.com/heated-dew-shields-lens-shades-celestron-telescopes_c393.aspx|title=Heating element|publisher=astronomics.com|accessdate=November 20, 2017}}