Pegasus Astro Motor Focus Kit Zero for Celestron SCT C11, EdgeHD 11 and RASA 11 v2

Product Overview

The Motor Focus Kit Zero is the motor-only version of Pegasus Astro's SCT focusing hardware — the same zero-backlash bipolar stepper, bracket, pulley and belt as the FocusCube Zero, but without the built-in controller. This is the 11" version, cut for the Celestron C11 Classic, EdgeHD 11 and RASA 11 v2.

Because the controller is not included, it needs one to drive it: a Pegasus Dual Motor Focus Controller, an Ultimate Powerbox v2, or an eXternal Motor Controller. If you already run one of those, this is the cheaper way onto the same mechanics.

Who It's For

This is a good match if you:

• Already own a Pegasus motor controller — a DMFC, a UPBv2 or an eXternal Motor Controller — and want to add motorised focus to an 11" SCT.
• Image with a C11, EdgeHD 11 or RASA 11 v2 and want repeatable absolute-position focus under software control.
• Are motorising a second telescope and would rather not buy a second controller for it.
• Run autofocus routines that depend on a focuser landing on the same number every time.

Key Features & Design

• Bipolar stepper, zero backlash: 1.8° step angle, 0.8 kg/cm hold torque, 0.18 kg/cm detent torque.
• Faster than the older Motor Focus Kit SCT it replaces, and free of the lash that skews an autofocus curve.
• 1:5 pulley ratio on the 11" and 14" versions: gearing matched to the heavier mirror-shift mechanism of the larger SCTs.
• RJ45 connection: a 1 m RJ45 cable is included for the run to your controller.
• Compact: 52 x 58 x 35 mm, 280 g including the bracket.
• Wide operating range: rated −40 °C to +80 °C.

Optical / Mechanical Design

An SCT focuses by shifting the primary mirror along the baffle tube, so focus position is set entirely by how far the knob has turned. The Motor Focus Kit Zero drives that knob through a timing belt and pulley rather than a gear train, and that choice is what produces the zero-backlash behaviour. A geared drive has lash on reversal: the motor turns, the knob does not, and the reported position no longer matches the real one. Every V-curve autofocus point built from those readings is then slightly wrong.

With the belt drive, a move to a given position lands on the same physical focus whether the approach was from inside or outside, which is what makes per-filter offsets and temperature-compensated focus worth using at all. The 1:5 ratio on the 11" bracket divides the stepper's 1.8° step into increments fine enough to sit inside the critical focus zone of an f/10 C11 or an f/2.2 RASA 11, while the 0.8 kg/cm hold torque carries an imaging train without slipping at the end of a slew.

Recommended Uses

• Adding motorised autofocus to a C11, EdgeHD 11 or RASA 11 v2 that already has a Pegasus controller on the rig.
• Motorising a second or third telescope from an existing Dual Motor Focus Controller.
• Temperature-compensated focus routines driven from the controller's own sensor input.
• Remote and observatory operation where focus is set from software.

Compatibility and Accessory Notes

• A controller is required and is not included. Pegasus Astro lists the Dual Motor Focus Controller, the Ultimate Powerbox v2 and the eXternal Motor Controller as the drivers for this motor. We stock those.
• This is the 11" bracket — Celestron C11 Classic, EdgeHD 11 and RASA 11 v2. The 14" and the 6"/8"/9.25"/RASA 8 versions are separate products, both of which we carry.
• Meade SCTs with the round focus knob are listed by Pegasus Astro as compatible.
• Want the all-in-one instead? The FocusCube Zero is the same mechanics with the controller built in and USB straight to the computer — the right choice if you do not already have a controller.
• Unsure which you need? Tell us what is already on your rig and we will work out whether the kit or the FocusCube is the better buy for you.

Good to Know Before You Order

• This is a motor, not a complete focus system. Without a Pegasus controller on the rig it will not move. If you are starting from nothing, the FocusCube Zero is the one-box answer.
• Aperture-specific bracket. The kit is sold per telescope size because the bracket and pulley bore differ — this one is the 11" fit.
• What is in the box: the motor, the aluminium bracket, the timing belt, the pulley, screws and washers, and a 1 m RJ45 cable.
• Pegasus Astro publishes 280 g including the bracket on the Motor Focus Kit Zero page. That is well under a pound, so our declared 1 lb shipping weight is the carrier minimum rather than the true mass.

Frequently Asked Questions

Is it difficult to set up?

The mechanical fit is straightforward — bracket, pulley and belt onto the focus knob, with the screws supplied. The electrical side is one RJ45 lead to a controller you already have, and the focuser then appears in ASCOM or INDI through that controller.

Do I need to buy a controller as well?

Yes, unless you already have one. A Dual Motor Focus Controller, an Ultimate Powerbox v2 or an eXternal Motor Controller will drive it.

How is this different from the FocusCube Zero?

Same motor and mechanics; the FocusCube Zero adds the controller electronics and a USB port, so it works on its own.

Will it fit a C14?

No — the C14, EdgeHD 14 and RASA 14 take the 14" kit. We stock it.

Does it come with a temperature sensor?

No. Temperature sensing comes from the controller, and the matching probe is a separate part depending on which controller you run.

Bottom Line

In short: the zero-backlash stepper, bracket, pulley and belt for a C11, EdgeHD 11 or RASA 11 v2, ready to plug into a Pegasus controller you already own. Add the controller and it becomes a full autofocus system.