AstroTech Dielectric 1.25" 90 Degree Diagonal Mirror for Telescope For Sale
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AstroTech Dielectric 1.25" 90 Degree Diagonal Mirror for Telescope:
AstroTech Dielectric 1.25" 90 Degree Diagonal Mirror for Telescope( Open Box - Demo - Like New - Excellent Condition )
- 99% Reflective Dielectric Coated 1.25 inch works with refractor & catadioptric telescopes.
- Diagonal comes with both dust covers, keep your lens clean for superior image fidelity.
- 90 degree angle, stand and just look down with a comfortable observing angle.
This 1.25" dielectric mirror-type star diagonal was a Sky & Telescope Hot Product for 2007! Considering
its performance, it would be an outstanding value at twice the price.
At its economical low price, it's still a hot product, and nothing short
of sensational . . .
The Astro-Tech 1.25" diagonal has state-of-the-art 46-layer dielectric
mirror coatings for a full 99% reflectivity. This is markedly higher
reflectivity than the 88% of a conventional aluminum diagonal or the
96-97% of an easily-tarnished silver diagonal. The result? Extremely
faint deep space objects at your scope's performance limits become more
visible, changing your viewing from "I guess I see it" to "it's really
The mirror housing is precision-machined from solid
aluminum, rather than simply flimsy Bakelite plastic or a sheet metal
stamping, as you'll find with ordinary diagonals. A rigid machined metal
backplate with stainless steel hardware holds the mirror in perfect
optical alignment in the machined body. The interior of the body is
anodized an antireflective matte black. The focuser-side barrel is also
anodized antireflective matte black, and is internally antireflection
threaded for even higher contrast. The barrel is threaded to accept
standard 1.25" filters.
The 1.25" eyepiece holder uses a
non-marring soft brass compression ring to clamp eyepieces in place,
rather than a thumbscrew that can scratch an eyepiece barrel by
tightening down on it directly.
A shallow slanted groove cut into
the outside of the focuser-side barrel engages with the scope's visual
back or eyepiece holder thumbscrew to act as a safety stop. This keeps
the diagonal from falling should the scope's thumbscrew loosen slightly
from cold or use. Dust covers are provided for both sides of the
This premium 1.25" diagonal works with virtually any
Schmidt-Cassegrain, Maksutov-Cassegrain, or refractor that uses a 1.25"
star diagonal,. It will provide a visible improvement on deep space
objects over the scope's factory-supplied diagonal. The newly designed
body of the Astro-Tech diagonal is more compact than previous diagonals.
This essentially eliminates any possibility of the diagonal bumping
into the drive base of a short fork arm catadioptric when the scope is
pointed at the zenith. This Sky & Tel Hot Product gives you all the visual performance your scope is capable of delivering, at a price that's very affordable.
1 Piece 90 Degree Diagonal Mirror with dust caps