Meade
#673 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 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.
Meade
#673 compatible flexible dew shield cap
in the retracted Position
Meade
#673 compatible flexible dew shield cap
in the extended Scope Protector Position
How
to prevent dew on you telescope
Use
a flexible dew shield cap
Use
a "Dew Heater" which uses electrical
power to raises the temperature of the front lens
of the telescope.
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.
Advantages
when using a dew shield cap
Prevent
dew condensation allow you to enjoy star gazing.
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.
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.
Your
ETX-90EC telescope will fit in the hard case very
nicely with the flexible dew shield cap Scope Protector installed.
You
install the flexible dew shield cap on the telescope and leave
it on the telescope.
Slip
the flexible dew shield cap forward and put it to work: prevents
dew forming and block out stray light..
Slip
the flexible dew shield cap backwards and it PROTECTS
your telescope tube from accidental scratching.
Your
telescope will fit in the hard case without removing
the flexible dew shield cap.
The flexible dew shield cap is made of Neoprene/Vinyl/Nitrile,
a black closed cell Foam Rubber sheet which
is , oil-resistant,
ozone-resistant, and fire-retardant.