Dew Shield for Celestron NexStar 5i Telescope

How dew forms?
When air temperature drop to a certain point at which moisture in the air condense on cool surface. The temperature when dew start forming is called the dew point. The condensed moisture as water droplet is dew. Dew is what prevents you from enjoying star gazing with you telescope at cold nights. As long as the temperature is below dew point, dew will continue to form on your telescope no matter how often you wipe the telescope. Dew shield traps the air and

How does Dew Shield Work?
Dew Shield traps stagnated air in the front of the telescope. The temperature of the stagnate air is slightly higher and prevents dew from forming. This slight different in temperature is enough to stop the dew from forming.

Dew shield can also be use as a lens shade to blocks stray light from entering the telescope. Stray light lowers the contrast of the viewing image. This is especially obvious and important in daylight torrential viewing.

Advantages of our flexible dew shield

Our flexible dew shield is made of black close cell foam rubber material which is oil resistant, ozone resistant and fire retardant.

The close cell foam rubber sheet a very good insulator which will maintain temperature much longer that other plastic material.

The non-reflective flat black matt surface is essential to eliminate glare cause by stray light.

The close cell foam rubber material is 1/8" thick, light weight, yet firm and rigid to maintain cylindrical shape.

What is the disadvantage of other dew shield?

I bought a dew shield that is make of flexible ABS plastics. This dew shield works well except that I have no where to store it. It can be lay flat when not in use. However, it is too long laying flat, too bulking when rolled up. It will not fit in my telescope hard case. There is no good way to store this dew shield. I end up leaving this dew shield when I take the telescope on trips. Lastly, the edge of the dew shield come apart when I roll up the dew shield tight.

Other dew shield that is make of flexible plastic do not have a matt interior surface and would reflex stray light and total defeat the purpose of have a dew shield shield.