GENERAL NEWTONIAN PRIMARY

Common Newtonian-style telescope primary configurations: These knobs will fit most Newtonian reflectors made by Guan Sheng Optical, including GSO, Hardin Optical, Meade, and Zhumell models. Our knobs listed here have a screw diameter of 7 mm (collimation) and 6 mm (locking), and will usually fit your telescope if you select the knobs that match your scope’s aperture. If your screws are different, we can design custom knobs for your application. Contact us using the link at the bottom of this page for more information.

We also offer stronger primary mirror support springs so collimation is retained while the locking screws are backed off for collimation adjustment. See Item D below.

A. Knobs for Newtonian 8” Primary

Part: MLB8pri
Fits: 8” Newtonian telescopes manufactured by Guan Shen Optical (GSO), including Meade LIghtbridge, Hardin Optical, and Zhumell.

Primary collimation
  • Knobs: Black plastic, 30 mm (1-1/4”) diameter, 5-point fluted
  • Threads: Plated steel
Primary Lock
  • Knobs: Black plastic, 25 mm (1”) diameter, knurled
  • Threads: Stainless steel
Notes:
  1. These knobs will fit telescopes with M7 (7 mm diameter) primary adjustment screws and M6 (6 mm diameter) primary lock screws. These knobs will not fit 8” GSO telescopes that have M5 (5 mm diameter) primary adjustment screws.
$29.95

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B. Knobs for Newtonian 10” Primary

Part: MLB10pri
Fits: 10” Newtonian telescopes manufactured by Guan Shen Optical (GSO), including Meade LIghtbridge, Hardin Optical, and Zhumell.

Primary collimation
  • Knobs: Black plastic, 30 mm (1-1/4”) diameter, 5-point fluted
  • Threads: Plated steel
Primary Lock
  • Knobs: Black plastic, 25 mm (1”) diameter, knurled
  • Threads: Stainless steel
$29.95

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C. Knobs for Newtonian 12” Primary

Part: MLB12pri
Fits: 12” Newtonian telescopes manufactured by Guan Shen Optical (GSO), including Meade LIghtbridge, Hardin Optical, and Zhumell.

Primary collimation
  • Knobs: Black plastic, 30 mm (1-1/4”) diameter, 5-point fluted
  • Threads: Plated steel
Primary Lock
  • Knobs: Black plastic, 25 mm (1”) diameter, knurled
  • Threads: Stainless steel
$29.95

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D. Springs for Common Newtonian 8”, 10”, and 12” Primary

Part: CNspr
Fits: Many Newtonian models (8”, 10”, 12”) except 16”

Primary mirror springs as supplied by the factory can sag from the weight of the mirror cell. Our stainless steel replacement springs are stronger and provide adequate support to maintain primary mirror collimation. We recommend that the mirror locking screws remain in place for additional control.

Notes:
  1. These springs will fit if your primary mirror cell looks like the cell depicted in the photos above.
  2. $16.95