A must-have in the wet British climate. During the night water molecules from the atmosphere condense on the front of the correction plate of your telescope. As soon as the surface of your telescope has cooled down sufficiently for dew to form, your viewing night is virtually over. Rubbing it off is pointless as it will keep forming. The only solution is dew prevention. This is where the dew shield comes in.
The dew shield is an extension of the telescope tube. The black coating of the shield also contributed to the prevention of diffused light. Furthermore, the dew shield helps to shield the lens from insects, dust and other dirty particles. In short, a dew shield is a vital accessory. Don’t let your viewing pleasure be disturbed halfway in the night by a few drops of dew! The ideal size for a dew shield is 1 to 1.5 times the objective diameter.