Bob's Knobs for Set Screw Secondary Common Newtonian

A. Knobs for Set Screw Secondary

Part: CNsec30 or CNsec35
Fits: Celestron C8-N/NGT, C10-N/NGT, Orion Astrograph, Astroview, SkyQuest XX and XT, Skyview, SkyWatcher, StarBlast, GSO, and many others.

Secondary Characteristics: 4-vane spider, a deeply recessed center screw, and factory headless set (grub) collimation screws. The secondary plate holding the screws is about 20 mm (3/4”) thick. This is a very common Newtonian secondary configuration.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel

Notes:

1. We offer knobs with screws having either 30 mm or 35 mm length. Order knobs with a screw length sufficient to allow the knobs to clear the secondary housing. Knobs with 30 mm screws are the most common in this configuration.

B. Knobs for 4-Vane Phillips Screw Secondary

Part: CNsec25 or CNsec35
Fits: Celestron Starhopper, Meade Lightbridge, many GSO, Hardin Optical, and Zhumell models

Secondary Characteristics: 4-vane spider, a deeply recessed center screw, and factory Phillips collimation screws. The secondary plate holding the screws is about 20 mm (3/4”) thick.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel

Notes:

1. The factory collimation screw length, measured below the head, can be either 25 mm or 32-35 mm. Order knobs with the correct screw length for your application. Knobs with 35 mm screws are the most common.

C. Knobs for 3-Vane Phillips Screw Secondary

Part: CNsec25
Fits: Early Orion SkyQuest XT series and a few others

Secondary Characteristics: 3-vane spider, a shallow recessed center screw, and factory Phillips collimation screws. The secondary plate holding the screws is about 6 mm (1/4”) thick.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel

 

 

ASTRO-TECH

We offer knobs for the Astro-Tech Imaging Newtonian (IN) series and Dobsonian (D) series secondary. Select knobs for your telescope from the list below.

A. Knobs for Astro-Tech AT6IN, AT8IN, AT10IN, and AT12IN Imaging Newtonian Secondary

Part: CNsec35
Fits: Astro-Tech AT6IN, AT8IN, AT10IN, and AT12IN imaging Newtonian telescopes.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel
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B. Knobs for Astro-Tech AT8D, AT10D, AT12D, and AT16D Newtonian Secondary

Part: CNsec35
Fits: Astro-Tech AT8D, AT10D, AT12D, and AT16D Newtonian telescope.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel

Knobs for Celestron Starhopper 12” f/5 Secondary

Part: CNsec35
Fits: Celestron Starhopper (6”, 8”, 10”, 12”) Newtonian telescopes

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel