Most refractors come supplied with a dewshield but adding one to other telescopes can improve image contrast, stop dew from falling on exposed optical surfaces and provide some protection from prying fingers if your astronomy is a group activity! Maksutovs and SCT type designs benefit most from this accessory.
Perhaps you live or observe in an area of extreme condensation, maybe near a river or pond. Many parts of the UK can be affected by this.
When a mechanical solution to dew control is not enough, help is at hand. By heating the vulnerable optical elements to a fraction of a degree above the ambient temperature it is possible to prevent condensation from forming at all on vital optical surfaces, without distorting the precise optical surfaces & introducing distortions.
Invaluable for visual observing. Indispensible for astro-imaging.
Jim Kendrick from Canada was the pioneer here, and his products remain cutting edge and the best for purpose and we thoroughly recommend them to all of our customers. Higher levels dew controller systems can be run from a PC or laptop and sense not only temperature but humidity too for optimum control. Call Simon for advice if necessary.