Steeldrive II Motor Unit

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Steeldrive II Motor Unit

# 2957265

€ 275.00 Price excl. German VAT tax (19%): € 231.09

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  • High-precision focusing motor for heavy loads (up to 8 kg), incl. temperature sensor, supports temperature compensation.
  • Works with every Baader Steeltrack® focuser (Classic and Diamond)
  • Please note: The motor unit requires the Steeldrive II Controller (#2957260 , € 445,-) . You always need one controller to operate one motor unit. But you can use one controller with several motor units one at a time – you only need to plug it into the motor unit which you want to use.
  • Can also be used with other focusers like e. g. FeatherTouch. Adapters for other focusers are in development, but not included in the scope of delivery.
  • Contactless Homing Sensor enables precise homing and repeatable ap- proach of saved absolute positions – perfect for remote-observatories.
  • Can be controlled either with the powerful SteelGo II software or through the ASCOM driver. Needs Steeldrive II Controller (#2957260 , € 445,-)
  • Made in Germany: The housing is CNC-milled from Aluminium in our factory. The electronical boards are made by a German company according to our specifications.

Product Questions and Answers

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How can I make sure that always the same COM-Port is used?
Question by: Matthias on Oct 1, 2021 1:27:00 PM | 1 Answer(s)

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Is it possible to operate the Steeldrive II with just ASCOM? I am doing that with the old classic Steeldrive.
Question by: Clement Elechi on Dec 12, 2019 10:08:00 PM | 1 Answer(s)

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Baader Steeldrive II motor focuser for Diamond Steeltrack® Focusers and other Focusers

The SD II motor unit is designed to be operated with the SD II control unit. If you want to use the motor without the Stedldrive II Control unit, you can find a diagram with the pin configuration for a self-made control in our manual (pdf). A control unit can control one motor unit at a time, but you can use a computer to control several controllers parallel.

The motor is designed to move to a saved position with highest precision if it is used together with the homing sensor – even if it has to move several kilograms over the complete travel of the focuser! The Steeldrive II Motor Focuser includesone motor unit with belt drive and a 3m long connection cable. It can be connected to all Baader Steeltrack® and Diamond Steeltrack® focusers. A 3D-printed magent holder for homing sensor, which can be attached to the focuser. For Baader Diamond Steeltrack® focusers, a Metal Magnet Ring for Homing Sensor (Steeldrive II) (#2957264 , € 73,-) is available separatley.

The motor unit of the Baader Steeldrive II can easily be attached to focusers with a dovetail clamp. A Baader Diamond Steeltrack® focuser ialready provides a matching 25mm dovetail, as well as the previous Classic 2" or 3" Steeltrack® modells (25 mm or 27 mm dovetail). Other focusers can also be used, but they may need other adapters, which will either be offered by us in the future or must be custom-made by you.

SD II Motor Unit

SteelGo II Software

SD II Controller

Video: Steeldrive II – Installation of
Motor Unit and Magnet Holder

Video: SteelGo II – Working with the Software

Video: Steeldrive II – Controller
Installation and Functions

Scope of Delivery of the Motor Unit for Steeltrack® Focusers

  • Steeldrive II (SD II) motor unit for Steeltrack ® focusers
  • CAT 7 cable (3 m) to connect the control unit
  • SD II toothed belt for Steeltrack® focuser
  • Temperature sensor with phone connector. Can be used with SD II motor units or SD II control units
  • Magnet holder for homing-sensor – can be used with Diamond Steeltrack® and similar focusers, includes mounting screw
  • Allen key (2 mm)
  • Velcro tapes (cable ties) for strain-relieving cable management

Optional Accessories:

For further accessories like adapters to use the SD-II motor unit with other focusers, please visit


  • High precision focusing of heavy loads
    The high-torque stepper motor is directly engaged with the focuser via a timing belt. This eliminates the backlash (and potential cause of defects) induced by gearboxes which would have to be used with lower power motors. The Steeldrive II can quickly move loads up to 8 kg with high precision. The focusing resolution is 2.5μm. 
  • Intuitive Operation. The motor unit requires the Steeldrive II Controller (#2957260 , € 445,-) .
    The intuitive hand control makes it possible to find and save the focus point very fast. Several modes are available to move the focuser:
    Normal mode: The focuser moves as long as a key is pressed.
    Jogging mode: Each keystroke moves the focuser for a distance which is configurable in the SteelGo-software (e.g. 0.1 mm).
    Single step mod: Each keystroke moves the focuser for the smallest possible way (ca. 2.5 micrometer).
    The configuration of limits, saving and resetting of positions and (de)activating of the temperature control can also be done with the hand control. Brightness of backlight illumination and status LEDs are also configurable.
  • Contactless Homing Sensor
    The Steeldrive II motor unit features a contactless (wearfree) homing sensor (hall-effect sensor). It is activated by a magnet attached to the moving part of the focuser. It enables precise homing and repeatable approach of saved absolute positions as well as reference of the mechanical endstop. A simple mount for this magnet to be attached to the focuser is included in the scope of delivery. For Baader Diamond Steeltrack® focusers, an adapterring made of metal is available separately.
    However the Steeldrive II can also be used without the homing sensor as the absolute position is kept in a persistant circular eeprom buffer. Even if a power failure occures, the absolute position is loaded upon restart of the Steeldrive II, as long as the focuser wasn't moved by hand.
  • Temperature Compensation
    Two digital temperature sensors may be used simultaneously. One of each may be connected to the motor- and the controller unit. For the automatic temperature compensation, the specific sensor to be used can be selected, or the average temperature of both sensors may be used (eg. measuring the temperature above and below the telescope tube, or inside and outside), depending on your needs. The temperature compensation factor is for example calculated with the SteelGO software and can then be saved locally on the Steeldrive II controller unit. The compensation period and ∆T threshold can also be adjusted. The temperature compensation may then also be used in standalone mode of operation (without a connected computer).
  • 12V/1A PWM power output (PID-controllable)
    The Steeldrive II features a 12V/1A power output. It can be used with an optionally available adapter cable from Steeldrive II Controller AUX Port to Cinch with common dew-cap heaters #2957262 with up to 10W. The power can either be set in the SteelGo software, or you set a desired temperature for one of the temperature sensors. This prevents undesired heating of the telescope, because you keep the dew cap just above the dew point. It can also be used to control the exact temperature (+/-0.1 °C) of e.g. optical filters.
  • Made in Germany
    All mechanical parts are CNC-milled from Aluminium in our workshop. The electronical boards are also designed and made in Germany. We only use high-end electronical components. The electronic circuit boards are additionally protective coated.
  • Low Power Consumption
    The motor current is automatically reduced while in holding state. The Steeldrive II then consumes approximately 0.7 W.

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Additional Information

Manufacturer Baader Planetarium
SKU (#) 2957265
Net weight (kg) 0.35
EAN Code 4047825038968
Payload Capacity (kg) up to 8 kg
Resolution appr. 2,7 micrometer per step
Power Output 12V/1A PWM
Power consumption ca. 0,7 Watt
Software SteelGo Software (Download)
Material Aluminium

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