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Secondary mounts FAQ

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Thin vanes for low diffraction.
Unique simplified collimation procedure.
Optional anti-dew heater available.
Two mirror mounting methods to accommodate any mirror size.
Graphite-impregnated flat black finish.
Includes mounting hardware, drill bit, and installation instructions.

Protostar secondary mounts are professional quality optical mounts designed for the lowest possible diffraction, and simplified collimation adjustment. The secondary mirror can be mounted either with the metal shroud, or adhesively mounted directly to the face of the holder. (The adhesive method must be used for non-standard mirror sizes.)

The collimation adjustment screws are conveniently located on the face of the spider hub. Both the spider hub and the secondary holder bodies are made of an energy absorbing material making them inherently vibration resistant, and a specially-blended graphite impregnated flat black paint is used to reduce light scatter.

Optional features are a built-in wireless antidew heater, and custom offsets can also be specified when ordering. 3.50" and 4.00" models feature special heavy-duty spider construction. Available in metric threaded versions.

Each secondary mount kit includes the spider, mirror holder, collimation tool, drill bit for installation, mounting screws, and instructions. Made in the U.S.A.

Read how to order secondary mounts...

More detailed information about this product...

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Download the installation instructions for secondary mounts.

See also:
3-vane secondary mounts.

Available Options
An anti-dew heater, built-in offset, and metric threading are optional features you can have built in to your secondary mount. See more details...

Prices include both spider and mirror holder.

The tube ID ranges shown in the table are for pricing purposes only, and the spiders are not adjustable over this wide range. We make your spider to fit your exact tube requirements. When ordering, please provide the actual tube (or cage) inside diameter. We will make your spider slightly smaller to permit proper vane tensioning.

The dimensions in the table are in inches.

Note: Spiders are custom-made for your inside diameter (ID), and are not adjustable over the ranges shown in the table below. When ordering, provide the information described on the ordering information page.

Secondary size

4.50" to 11.50" tube ID

11.51" to 15.50" tube ID

15.51" to 22.50" tube ID

22.51" to 31.50" tube ID





























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Protostar P.O. Box 368 New Albany, Ohio 43054 U.S.A. 614-375-3146 (<< new phone & address as-of March 2018!)
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