Bob's Knobs for MEADE 8” (20 cm) SCT

Bob's Knobs for MEADE 8” (20 cm) SCT

We offer knobs for all versions of the Meade 8” f/10 and f/6.3 Schmidt-Cassegrain secondary, including those with three, four, and six secondary screws. (The extra screws on the four- and six-screw versions are for secondary disassembly, not collimation.)

Select knobs for your telescope from the list below. Please use care to select the correct knobs for your telescope. Each knob set is different and they are not interchangeable. Price is for a complete set of knobs.
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A. Knobs for Meade 8” f/10 with 3-Screw Secondary

Part: M8-3
Fits: Meade 8” (20 cm) f/10 SCT versions with three screws on the secondary housing (2080, LX5, LX10, LX50, LX90, LX100, LX200, others)

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Black anodized aluminum alloy

Notes:

1. The factory dust cover may contact the knobs when installed. We provide a set of spacers that attach to the inside of the dust cover to move it slightly away from the secondary assembly. You can also press the center of the cover from the inside to contour it for additional clearance.
2. Some post-2004 Meade 8” telescopes have four screws or six screws on the secondary housing. The 4-screw and 6-screw secondary require different knobs (Items B and C below) Do not use knobs for the 3-screw secondary on the 4-screw or 6-screw secondary. The screws on 3-screw knobs are too short.
3. Some very early Meade 8” model 2080 telescopes have two collimation screws. Please contact us using the link at the bottom of this page for knobs to fit this scope.
4. An Allen wrench for removing the factory collimation screws is included with your order.

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B. Knobs for Meade 8” f/10 with 4-Screw Secondary

Part: M8-4
Fits: Meade 8” (20 cm) f/10 SCT versions with four screws on the secondary housing (LX90, LX200, others).

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

Notes:

1. Two sets of knobs, each with a different screw thread length, are included with your order. Use the thread length (measured below the white spacer) that matches the factory screw thread length.
2. The factory dust cover should fit normally with Bob's Knobs installed. If your dust cover contacts the knobs, we provide a set of spacers that attach to the inside of the dust cover to move it slightly away from the secondary assembly. Contact us for a free set. You can also press the center of the cover from the inside to contour it for additional clearance.
3. Pre-2005 Meade 8” telescopes have three screws on the secondary housing and no fourth screw on the side. The surface of the 3-screw secondary is textured, not smooth like the surface of the 4-screw secondary pictured. The 3-screw secondary requires different knobs (Item A above).
4. An Allen wrench for removing the factory collimation screws is included with your order.

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C. Knobs for Meade 8” f/10 with 6-Screw Secondary

Part: M8-6
Fits: Meade 8” (20 cm) f/10 SCT versions with six screws on the secondary housing (LX90, LX200, LX200ACF, LX200R, LS-8 SC and ACF, LT-8 SC and ACF, others). The inner screws are for collimation.

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Black anodized aluminum alloy

Notes:

1. The factory dust cover fits normally with Bob's Knobs installed on most versions. If your dust cover contacts the knobs, we provide a set of spacers that attach to the inside of the dust cover to move it slightly away from the secondary assembly. Contact us for a free set. You can also press the center of the cover from the inside to contour it for additional clearance.
2. See our FAQ and technical paper for additional information on installing Bob's Knobs on Meade telescopes with six factory secondary screws.
3. Your user manual from Meade may claim that the outer secondary screws are for collimation adjustment. This is incorrect. The inner screws (with knobs in our photo) are collimation screws. The outer screws are for disassembling the secondary.
4. Pre-2005 Meade 8” telescopes have three screws on the secondary housing. The 3-screw secondary requires different knobs (Item A above). Do not use knobs for the 6-screw secondary on the 3-screw secondary. The screws on the 6-screw knobs are too long.
5. An Allen wrench for removing the factory collimation screws is included with your order.

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D. Knobs for Meade 8” f/6.3 Widefield Secondary

Part: M8wf
Fits: Meade 8” (20 cm) f/6.3 SCT versions (2080, LX6, LX10, LX50, LX100, LX200) which are marked f/6.3 WIDE-FIELD (or a variation of this) on the corrector ring

Knobs: Stainless steel, 12 mm (1/2”) diameter
Threads: Stainless steel

Notes:

1. Since the factory dust cover contacts the secondary housing when installed, additional clearance is needed to make room for the knobs. We provide a set of spacers that attach to the inside of the dust cover to move it slightly away from the secondary assembly. You can also press the center of the cover from the inside to contour it for additional clearance.
2. An Allen wrench for removing the factory collimation screws is included with your order.