This is my new, never used, ProtoStar 1.52" ULS Quartz secondary mirror with 3-vane mount.
I purchased these about 10 years ago and plan to upgrade my secondary mirror but never had a chance to do it.
Please contact me if you have any questions.Thank you very much for your business!
P.S.: you may also purchase this item in Astromart classified ads:
Please see the detailed information below from ProtoStar website:Secondary Mirror Features:
Applications include reflector telescope secondary mirrors, optical bench set-ups, or reference flats.
Each piece is serialized, tested, and supplied with an interferometric report. (0.1 p-v is the minimum flatness quality.)
10-5 scratch/dig, and 2-4 nm rms micropolish roughness for low laser scatter.
High-efficiency 96% (avg visible reflectivity) broadband coating.
Dielectric overcoating applied with ion-assisted deposition (IAD) process for enhanced durability [meets or exceeds MIL-M-13508 (260 kB pdf)].
Suitable for visible, near-IR, and near-UV low-power laser
applications. (Laser damage threshold is 70 W/cm² (20 Hz cyclic) at 1064
CNC machined fused silica substrate for a precise fit into the holder.
ULS Quartz mirrors make superb Newtonian telescope secondary mirrors, or
low-scatter laser mirrors. They can be used in temperatures from
cryogenic temperatures (-200º C) to over 500º C, while retaining their
surface accuracy. Their surface accuracy is not affected by localized
temperature gradients like those generated by antidew heaters, or other
nearby heat sources.
3-Vane Mount Features:
Thin vanes for low diffraction.
Unique simplified collimation procedure.
Carbon composite mirror shroud securely retains the mirror without strain.
Available for any size of secondary mirror.
Low-scatter surface texture.
Our 3-vane spider design has 1/4 less total diffraction
compared to 4-vane models. Bright field objects will appear to have six
diffraction spikes spaced at 60° intervals, but the spikes are half as
bright compared to a 4-vane spider. The 3-vane mounts feature the same simplified collimation as the 4-vane models. Made in the U.S.A.
Filed under: Eyepieces & Accessories