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Eliminates concentrated diffraction artifacts (i.e., diffraction spikes).
Low total diffraction design.
New featherweight carbon composite hub & holder design.
Easy-to-access collimation adjustment screws.
Available for any size secondary mirror up to 2.60" minor axis.

Note: Curved mounts can be installed in solid-tube telescopes up to 15" inside diameter.

Protostar curved mounts are available for secondary mirror sizes up to 2.60", and solid tubes with inside diameters up to 15-inches. They not only eliminate diffraction spikes (see diffraction comparison image), but also minimize total diffraction. The arch is made of thin steel, and the 180Âș curve symmetrically spreads diffraction. The unique tapered design of the arch increases rigidity while minimizing the side scatter from the arch. The arch is also invisible from the focal plane, which eliminates direct scattered light from the secondary support.

Fully adjustable positioning

Two brackets attach the arch support to the tube wall, and each bracket is fully adjustable for variations in tube size. This also permits custom secondary offsets where necessary. Each bracket can also be rotationally adjusted to insure the arch is perfectly edge-on to the primary mirror to further minimize diffraction.

Read more about how to install and use the curved mounts in the illustrated installation instructions (975 kB pdf).

Same easy collimation features as our straight-vane mounts

The curved mount features the same simplified collimation adjustment design of our straight-vane mounts. Read more about the collimation features on the straight-vane mountings for a complete description.

Technical highlights

For a complete discussion of the technical aspects of our curved secondary mount, please refer to the curved secondary mount FAQ. Made in the U.S.A.

Each kit includes:

curved arch support

collimation tool

mirror holder assy

tube drilling template

mounting brackets


Read how to order secondary mounts...

Detailed Product Images
(click to enlarge)

Download the installation manual for curved secondary mounts.

Prices include both the support arch and mirror holder.

The tube inside diameter (ID) ranges shown in the table are for pricing purposes only, and the curved mounts are not adjustable over this wide range. Your curved mount will fit your exact tube requirements. When ordering, please provide the actual tube inside diameter.

The dimensions in the table are in inches.

Curved mounts are custom-made for your inside diameter (ID). When ordering, provide the information described on the ordering information page. The table below shows some common sizes, but we can make a holder for any mirror size (up to 2.60" m.a.).

Secondary size (minor axis)

6.0" to 10.5"
tube ID

10.51" to 15.0"
tube ID

























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