Meade #673 dew shield compatible dew shield

Meade #673 dew shield Compatible flexible dew shield for
Meade ETX-90EC Telescope

Meade #673 dew shield compatible flexible dew shield prevents dew condensation allow you to enjoy star gazing. When air temperature drop to a certain point at which moisture in the air condense on cool surfaces.  The  temperature at which 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.  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.

Meade #673 dew shield compatible flexible dew shield also Blocks stray light from entering the telescope.  Stray light lowers the contrast of the viewing image.  Blocking out stray light will increase the image contract.  This is especially obvious and important in daylight viewing. It improves astronomical viewing and astronomical photographic contrast from city observing sites by blocking neighboring stray lights. It also gives a considerable improvement in contrast during daytime terrestrial viewing and is highly recommended for daytime terrestrial photography.

How does flexible dew shield cap Work
flexible dew shield cap traps stagnated air in the front of the telescope.  The temperature of the stagnate air is slightly higher than ambient temperature and thus prevents dew from forming. This slight different in temperature is enough to stop the dew from forming.   

What is the disadvantage of other dew shield cap
I bought a brand name flexible dew shield cap.  It is make of flexible hard plastic and form the flexible dew shield cap with Velcro strips. This flexible dew shield cap 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 bulky when rolled up.   It will not fit in my telescope hard case.  There is no good way to store this flexible dew shield cap.   I end up leaving this flexible dew shield cap home when I take the telescope on trips.  Other flexible dew shield caps that are made of hard plastic have the same storage problem.  It is not convenient.