Skip to content
Price match 30-day returns* Talk to an astronomer before you buy
Starlight Instruments Electronic Focusing System

Starlight Instruments Electronic Focusing System

by Starlight Instruments
SKU SI-EFS-01
CA$420.00 - CA$434.00
CA$420.00
CA$420.00 - CA$434.00
CA$420.00
Price Match Policy!
  • ASCOM driver for any ASCOM compliant software
  • Backlash correction, temperature compensation, focus lock and motor braking
  • Hand controller with 1, 10 or 100 steps per detent
  • Control box 4.13" x 2.87" x 1.1" (105 x 73 x 28 mm)
  • Runs HSM20, HSM30 and HSM35 motors, or the PDMS (sold separately)
Power Supply
Backordered
Request Stock Alert
Availability Info
Qualifies for FREE Shipping in Canada on orders over $500.
Focus Step Calculator

Set the right autofocus step

Get the autofocus step size for the Starlight Instruments Electronic Focusing System with your telescope and camera, in each capture program.

Calculate step size
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Starlight Instruments Electronic Focusing System

    The Starlight Instruments Electronic Focusing System (EFS) is a stepper motor controller for Starlight's HSM and PDMS focus motors. The control box measures 4.13" (105 mm) long, 2.87" (73 mm) wide and 1.1" (28 mm) thick, and connects to your computer by USB with an ASCOM driver that offers backlash correction, temperature compensation, motor braking, focus lock and several speed settings. The included hand controller moves the focuser 1, 10 or 100 steps per detent.

    The EFS Control Box

    The control box and hand control are lightweight and compact. The box links your PC to the focuser motor over a standard USB cable, and the EFS comes with an ASCOM driver that works with any ASCOM compatible program. The system draws a maximum of 1 amp at 12V.

    Power, the hand controller and USB connect at the rear of the box, and the focuser motor connects at the front. The motor connects by Ethernet cable and the hand controller by RJ11 cable, and Starlight supplies all the cables.

    Hand Controller: 1, 10 and 100 Steps per Detent

    The included hand controller plugs into the port on the back of the box. Turning its knob moves the focuser, and you can feel a detent for each movement. Clicking the knob changes the movement per detent between 1, 10 and 100 steps, and a light on the controller shows the rate by color. Pressing and holding the knob turns extended functions on and off, such as temperature compensation, focus lock and zeroing the focus position. You do not need the hand controller plugged in to use the EFS with a computer.

    • Red: 1 step per detent, which can come in handy when using a scope visually or doing planetary imaging and adjusting focus by hand.
    • Amber: 10 steps per detent.
    • Green: 100 steps per detent, for larger moves.

    Motors: HSM and PDMS

    The Electronic Focusing System runs Starlight's Handy Stepper Motor (HSM) or Posi Drive Motor System (PDMS); the motor is sold separately and connects to the box by Ethernet cable. Choose the HSM made for your focuser. For heavier image trains and non Feather Touch focusers, Starlight offers the PDMS, which can lift in excess of 56 pounds.

    • HSM20 Motor: Compatible with Feather Touch Micro Focusers, retrofit pinion assembly upgrades, and Feather Touch Crayford focusers.
    • HSM30 Motor: Designed for 2.5", 3.0", and 2.0" Feather Touch Rack/Pinion focusers, as well as Astro-Physics 2.7" focusers with a Feather Touch pinion upgrade.
    • HSM35 Motor: Drives the large 3.5" Feather Touch focusers and Astro-Physics 3.5" and 4.0" focusers equipped with a Feather Touch pinion upgrade.

    ASCOM Driver and Automated Features

    The EFS ASCOM driver requires at least ASCOM Platform 6 and interfaces with any ASCOM compatible program. Backlash correction and temperature compensation are among the standard features, and the driver offers settings for braking the focus motor, locking the focus motor and several speeds.

    Backlash correction takes up mechanical play when the focuser changes direction, which helps an autofocus routine return to the same position. Starlight's Handy Motors have built-in temperature compensation, and temperature compensation is switched on and off from the hand controller. Firmware updates are also done through the hand controller.

    EFS vs. Focuser Boss II: Choosing the Right Starlight Controller

    Starlight Instruments offers two electronic focusing controllers. The EFS runs one focuser from a compact box over USB, with a hand controller included.

    The Focuser Boss II, by contrast, hub has Serial, USB and wired Ethernet connections, an optional WiFi board, and can control a second focuser with an optional 2nd focuser board.

    Note: The power adapter chosen at purchase is included. A compatible Starlight Instruments focus motor (HSM or PDMS) is needed to drive the focuser.

  • What software is compatible with the Starlight Instruments EFS?

    The Electronic Focusing System uses an ASCOM driver, which interfaces with any ASCOM compatible program and requires at least ASCOM Platform 6.

    Which Starlight Instruments motor do I need for my EFS and telescope?

    The correct motor (sold separately) depends on your specific focuser. The EFS is compatible with Starlight Instruments HSM and PDMS motors.

    • HSM20: Fits Feather Touch Micro Focusers, Feather Touch retrofit pinion assemblies, and Feather Touch Crayford focusers.
    • HSM30: Fits 2.5", 3.0", and 2.0" Feather Touch Rack/Pinion focusers, as well as Astro-Physics 2.7" focusers with the Feather Touch upgrade.
    • HSM35: Fits 3.5" Feather Touch focusers, and Astro-Physics 3.5" and 4.0" focusers with the Feather Touch upgrade.

    How does the EFS hand controller change step sizes?

    Click the knob on the hand controller. Each click changes the movement between the three settings, shown by a colored LED: Red for 1 step, Amber for 10 steps and Green for 100 steps per detent of the knob.

    Can the Starlight Instruments EFS run without a computer?

    Yes. The included hand controller moves the focuser with the box powered at 12V, and its press-and-hold functions switch temperature compensation and focus lock on and off. The ASCOM driver and its settings need a computer.

    Is a motor included with the Starlight EFS?

    No. Choose a Starlight Instruments HSM20, HSM30 or HSM35, or a PDMS, to match your focuser; it is sold separately.

    How is the Starlight EFS powered in the field?

    The EFS runs on 12V and draws a maximum of 1 amp. The power option chosen at purchase is included: an AC/DC 12V power supply, a DC Cigarette Plug for a 12V DC source, or a European power adapter.

    What is the difference between the EFS and the Focuser Boss II?

    The EFS runs one focuser over USB and includes a hand controller with 1, 10 and 100 step settings. The Focuser Boss II hub adds wired Ethernet and Serial connections, an optional WiFi board, an ASCOM Local Server for several programs at once, and control of a second focuser with an optional board.

    Does the EFS offer temperature compensation?

    Yes. Temperature compensation is among the EFS features, and you turn it on and off by pressing and holding the hand controller knob. Starlight's Handy Motors come with built-in temperature compensation. It adjusts the focus position as the telescope cools.

    What does backlash correction do?

    Backlash correction is among the EFS features. Backlash correction takes up mechanical play when the focuser changes direction, so that moves made by an autofocus routine land where they are meant to.

    How do I update the firmware on the Starlight EFS?

    Firmware updates are done using the hand controller, as explained in the EFS user manual.

  • Motor Compatibility (HSM20) Feather Touch Micro Focuser, Feather Touch retrofit pinion assembly upgrades, and Feather Touch Crayford focusers
    Motor Compatibility (HSM30) 2.5", 3.0" & 2.0" Feather Touch Rack/Pinion focusers; Astro-Physics 2.7" with FT pinion upgrade
    Motor Compatibility (HSM35) 3.5" Feather Touch focusers; Astro-Physics 3.5" & 4.0" with FT pinion upgrade
    Control Box Dimensions 4.13" (105mm) L x 2.87" (73mm) W x 1.1" (28mm) H
    Connections Power, hand controller, USB (rear); focuser (front)
    Software ASCOM driver (requires ASCOM Platform 6 or later)
    Hand Controller Step Sizes 1, 10 or 100 steps per detent
    Automated Features Backlash correction, temperature compensation, focus lock, motor braking, multiple speeds
    Power Options AC/DC Power Supply 12V DC, DC Cigarette Plug, European Power Adapter (selected at purchase)
    Fits HSM20: Feather Touch Micro Focusers, Feather Touch retrofit pinion assembly upgrades, Feather Touch Crayford focusers, HSM30: 2.5", 3.0" and 2.0" Feather Touch Rack/Pinion focusers, Astro-Physics 2.7" with Feather Touch pinion upgrade, HSM35: 3.5" Feather Touch focusers, Astro-Physics 3.5" and 4.0" with Feather Touch pinion upgrade, PDMS motor

    • EFS Control Hub

      × 1

    • EFS Hand Controller

      × 1

    • USB Cable (A to B)

      × 1

    • Ethernet Cable (Hub to Motor)

      × 1

    • RJ11 Cable (Hub to Hand Controller)

      × 1

  • Starlight Instruments 1-Year Warranty on Electronics