Meade
#678 compatible flexible dew shield cap 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 #678 compatible flexible dew shield cap 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
#678 compatible flexible dew shield cap
Scope Protector
in the retracted Position
Meade
#678 compatible flexible dew shield cap
Scope Protector
in the extended Position
Yes!
my ETX-125EC has both the 90 degree and straight
through viewfinder and Electric focuser.
How
to prevent dew on you telescope
Use
a dew shield cap
Use
a "Dew Heater" which uses electrical
power to raises the temperature of the front lens
of the telescope.
How
does dew shield cap Work
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 dew shield cap. It is
make of flexible hard plastic and form the dew shield
cap with Velcro strips. This 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 dew shield cap.
I end up leaving this dew shield cap home when I take
the telescope on trips.
Other dew shield caps that are made of hard plastic
such as the original Meade dew shield have the same
storage problem. It is not convenient.
Your
ETX-125EC telescope will fit in the hard case very
nicely with the Meade #678 compatible dew shield
cap Scope Protector installed.
The
Meade
#678 Compatible flexible dew shield cap/Scope
Protector Advantage
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 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.