Secondary Telescope Pyrex Mirror 98-99% Reflective with DewGuard Diagonal Holder For Sale
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Secondary Telescope Pyrex Mirror 98-99% Reflective with DewGuard Diagonal Holder:
Secondary Telescope Pyrex Mirror 98-99% Reflective with DewGuard 9v in Diagonal Holder
Here we are offering a used secondary telescope mirror that was part of a scope incorporating the 25" parabolic mirror we have for sale (see other items).
Mirror housing has a diameter of 3.5" with an angled mirror measuring 4.75" x 3.5" approx.
A small dot is marked in the center for collimation.
Description from the owner:
"The secondary mirror is an enhanced reflectivity pyrex mirror, it is 98% or 99% reflective compares to normal aluminum coated only mirror 88%. Add to the 96%-97% main mirror you get the equivalent of nearly 2 inches of additional aperture. The secondary mounts in the diagonal holder that you have which is adjustable for colimational purposes, screw one side in and the opposite out to keep tension on it and so tilt the mirror, rotate with the main shaft and can be moved up or down via the main shaft, this shaft mounts in the spider holding it in front of the main mirror and also in front of the focuser of to the side of the secondary mirror, diagonal holder made by Astrosystems as is the type 3 spider in mounts in with this mirror, see link below: PS Astrosystems makes parts & whole scopes without mirrors.
The DewGuard glued to the back of the mirror is an automatic warmer to keep the dew off, if dew forms you need a hair dryer to remove or cover it and wait. It is design to keep the mirror 1 to 3 C above ambinant, The leads coming a battery lead use a 9V battery or connect to 12V DC, can use 8 to 16volts, the other is a temperture sensor & a LED light that lights when heating, plus a string that ties around the spider as a safety. See instruction for DewGuard"
Combined Shipping is ALWAYS an option as is LOCAL PICK-UP