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Dimensions and Specifications

Straight-vane secondary mounts

The following specifications are provided as general design and planning aids, and can be particularly useful when determining how a Protostar secondary mount will fit an existing telescope. The overhang dimensions listed (dimension 'A') are approximate, and you should not drill holes before receiving your secondary mount.

0.75", 1.00", and 1.30" models

The 0.75", 1.00", and 1.30" secondary mounts are all available with 3-vane spiders, and the 1.00" and 1.30" models are available with 4-vane spiders. The antidew heater option is not available on these smaller secondary mounts.

Metric spider versions use M5-0.8 threaded vane lugs (see options).

1.52", 1.83", and 2.14" models

The 1.52", 1.83", and 2.14" secondary mounts are all available with 4-vane or 3-vane spiders. The antidew heater option is available on all models. The spiders have one lug per vane for tube diameters under 12", and two lugs per vane for larger spiders.

Metric spider versions use M5-0.8 threading for both the collimation screws and the vane lugs (see options).

2.60", 3.10", 3.50", and 4.00" models

The 2.60", 3.10", 3.50", and 4.00" secondary mounts are available with 4-vane spiders. A 3-vane spider is available for the 2.60" mount for tube diameters up to 18". The antidew heater option is available on all models. The 3.50" and 4.00" models are heavy duty versions.

Metric spider versions use M5-0.8 threading for both the collimation screws and the vane lugs (see options).

Footnotes:

(1) Heavy-duty spider design features wider vanes, thicker vane material, and larger spider hub.

(2) For the 3.50" and 4.00" mounts, mirror thicknesses vary too much from different manufacturers, so this dimension should be measured directly with your secondary mirror installed.