TCSGalil™ Telescope Control Systems

This control system and it's predecessors are used on more professional telescopes than any other control system world wide. The DFM Engineering TCSGalil™ provides a user-friendly interface to the telescope.  Utilizing a PC with a display, keyboard, and mouse, you have continual position display, status reporting, and an easy-to-use, menu-driven command set.  Over the past decade, DFM has put considerable effort into completely redesigning the telescope control system and rewriting core software to provide our third and ultimate generation of our telescope control system.   

The feature set of the Third Generation brings new functionality.  No longer do servo motor tune-ups for the telescope require an oscilloscope to adjust potentiometers.  New software-controlled digital servo motor controllers allow tune-ups that can adjust for any servo imprecision on the telescope mount.  Optional Renishaw 26-bit absolute position encoders working with the controller to enable absolute positioning.  Now motor encoder reporting can be reconciled with that of the actual telescope mount positioning, closing the loop, to enable more precise, smoother, and accurate tracking of fast moving objects.  This option also increases productivity and telescope availability by eliminating the sometimes nightly zero-point procedure of locating a star near zenith in order to determine zero-point positioning, a procedure that can be particularly difficult for higher F-ratio telescopes (see our PFI™ page on how to retrofit these dinosaurs to do modern science).  Movement of the telescope, when the control system is powered off, no longer results in losing observation time running the zero-point procedure. Instead, with the Renishaw absolute encoders, the zero-point procedure will only be rarely required. 

A Renishaw linear travel absolute position encoder can also be installed on the focus motion to replace the existing sliding potentiometer / incremental encoder system, eliminating time spent searching for the fiducial, allowing precise focus positions to be returned to easily, a particularly useful feature when varying pre-determined focus positions are required for multiple instrumentation (check out our new Multiple Instrument Adapter) or filters.

This Third Generation DFM control system consists of two rack-mountable chassis: the computer chassis and the new Motor Driver Chassis (MDC). The computer chassis is a modern multi-core PC running the current version of the Windows operating system. The MDC is a custom DFM hardware unit that connects existing motors, motor encoders, position encoders, and cables with a Commercial Off-The-Shelf (COTS) multi axis Digital Motor Controller (DMC) from Galil Motion.

The communication between the observatory PC and the new TCS control system has been simplified to a single Ethernet cable, allowing the user to upgrade or replace PC hardware without worrying about compatibility with the mount hardware. The new MDC also increases control system robustness by including sacrificial daughter boards to address the leading cause of failure of previous ISA-based systems:  lightning-strikes.   This signal conditioning and surge protection hardware makes this unit well suited for observatory control room installations distant from the telescope.

On the software end, the TCS application has undergone a complete rewrite from the inside out. Starting with a well-defined philosophy for control logic and inter-system communication, the new TCSGO application was designed to handle frequent commands and queries from multiple sources, expanding the native command set, while maintaining high frequency control loops and a responsive user interface. Additional features available in the modern TCS include support for absolute on-axis encoders, closed-loop position control (with our unique Iterative Cubic Envelope Engine [ICEE]), and over 70 commands for unparalleled remote scripting and automation possibilities.  The new TCS software supports traditional remote commands delivered through a serial port or a TCP/IP connection as well as local commands delivered via the ASCOM standard (focus, dome, and telescope), introducing this feature-set to many older DFM telescopes. The end result is a unified code base that all customers share, handling all the features of multiple sites, in a single small executable.

Using ASCOM drivers for TCSGalil™, Focus, and Dome, TCSGalil™ may be commanded using TheSkyX, FocusMax, and ACP.  We optionally provide satellite tracking software to drive DFM Engineering Telescopes.

Our pointing model corrects for precession, nutation, aberration, atmospheric refraction, mount misalignments and flexure.  Typically, the DFM Engineering TCSGalil™ and pointing model will achieve 10 to 20 arc- second blind pointing to a 60° zenith distance.

All commands are available to your external computer, allowing you to create your own custom user interface where TCSGalil™ becomes a peripheral to your computer system, allowing integration with your own observing program.

Telescope Control System (TCSGalil™) Standard Features
Utilizing a PC with multiple displays and a keyboard, you have continual position display, status reporting, and an easy-to-use, menu-driven, command set.  TCSGalil™ operation is simple. Commands are divided into four submenus: initialization, movement, rates and miscellaneous.

Commands:
Commands are divided into four submenus: initialization, movement, rates and miscellaneous. All commands are available to your external computer, allowing you to create your own custom user interface where TCS becomes a peripheral to your computer system, allowing integration with your own observing program.

  • Control electronics may be located up to 150 feet from the telescope allowing flexibility in positioning the observatory control room.
  • More than 28 commands provide complete control of the telescope, dome, etc.
  • Includes a built-in library of objects
  • Compatible with DFM's Smart Auto Guider and other commercially available autoguider systems
  • Operates and displays in any epoch
  • Hybrid digital/analog servo controllers with zero position error integrator
  • 19 in. wide rack-mount houses control system computer and electronics
  • Extensive system protection via computer-calculated limits and hard limits
  • Hand paddle functions include: guide, set, slew, focus, dome right and dome left.
  • TCSGalil™ uses a single DC servomotor per axis to simplify mechanical and electronic requirements while enhancing maintainability.
  • CCT-16 system controls a focus stepper motor with potentiometer as the position sensor. CCT-20 and larger telescopes use an optical incremental encoder as the focus position sensors.  Renishaw absolute encoders are optionally available for focus control. 
  • Motor Driver Chassis (MDC) provides power supplies and surge protection components for interface with long cables to the telescope
  • Mother board design minimizes discrete wire connections in MDC
  • Low power usage minimizes uninterruptible power supply requirements
  • Limit switches enhance system safety by preventing telescope over-travel
  • Shielded cables with proper terminations maximize immunity to electronic noise
  • Gold-plated electrical connectors provide long-trouble-free service
  • Full wiring schematics provided for maintenance

     Options:

  • Renishaw absolute encoders upgrade
  • Remote monitor, keyboard, and mouse located in the dome for public night viewing and instruction where direct access to telescope is required
  • Remote hand paddle for use up to 1,000 feet from the controller