Why you need to have anti-dew strips to keep the moisture at bay.
Dew strips, or anti-dew strips, are insulated wires that get hot when electricity is applied. Just like a space heater (get it? space heater?) Except instead of keeping your feet warm, they keep your lenses warm. This prevents dew from forming after the temperature drops at night while you're imaging. Most dew strips have a RCA style connector on them (like old-fashioned TVs, VCRs, and DVD players before HDMI). You have to connect them to a power source which also acts as a controller. This controller can quickly turn the power on and off to keep the dew strip very carefully calibrated for the ambient temperature. Some things that help with this are a Pocket Power Box or other power distribution device, some of which have temperature sensors and do a great job of balancing power usage with keeping the dew off.