Key Features

  • Industrial control system for demanding applications
  • Programmable azimuth drive speeds with smooth acceleration
  • Intelligent handling of dropout door
  • Synchronized simultaneous motion of both doors
  • Linux-based embedded controller with redundant failsafes
  • ASCOM compliant with very intuitive interface
  • Communication by TCP/IP or serial port
  • Professional installation and training by ACE

ACE SmartDome Controller for Ash domes

The ACE SmartDome  is a fault-tolerant controller that allows an Ash Manufacturing Company (“Ash Dome”) product to be controlled locally, remotely and robotically.

It works with any ASCOM compliant software such as DC3 Dream’s ACP or TheSkyX or MaxIm-DL.

For professional clients wishing to integrate a dome controller directly into their software there is a comprehensive command library. Communication with the ACE SmartDome is through TCP/IP. An option to use a serial communications port is available.

We now describe the system in detail.

Full Description

The ACE SmartDome is designed for use in a professional observatory or public outreach facility where an industrial ruggedized control system is essential. Models are available for both 115 VAC and 240 VAC power options.

The system can be divided into two parts, those that are static (mounted on the wall of the observatory) and those that are dynamic, mounted on the moving part of the dome.

A set of (orange-colored) electric conductor bars (sometimes called slip rings) provide power to the rotating parts of the dome.  If you have an older Ash Dome these rings may be absent. ACE can retrofit these as part of the SmartDome installation.

The static components are:

  • Main control box with LCD display
  • Azimuth drive control box
  • Azimuth rotation motor(s)
  • Azimuth encoder
  • External weather station and cloud sensor

The dynamic components are:

  • Upper control box
  • Main shutter motor
  • Dropout shutter motor
  • Limit and interlock switches
  • Rain-snow sensor

The main control box and the upper control box communicate by a 2.4 GHz frequency hopping radio.  For radio-quite observatories we establish communication by installing three additional slip rings.

The main box has an LCD display which reports the current system status including the state of the two doors and the azimuth of the dome.  It contains useful diagnostics for an on-site observer.  However, the system is primarily designed for remote and autonomous robotic observing.

The on-site operator can control the dome using a series of push buttons.

The EMERGENCY STOP button halts all dome motion. (There is also a contact block to allow a signal to control the telescope emergency stop system).  This is a latching mushroom button.  Twist and release to restore functionality.

The OPEN and CLOSE push buttons control the main shutter door.

The DOWN and UP push buttons open and close the dropout flap or lower shutter.

The FORWARD and REVERSE buttons rotate the dome in the positive and negative azimuth (where North is 0 degrees and East is 90 degrees).

The upper box is similar to the main box except that there is no LCD display and there is no control for azimuth. 

The upper box is a self-contained system capable of intelligent closure of the two Ash shutter doors. In the event of a communications failure between the two boxes, or in the event of bad weather the dome will automatically close to protect the telescope.


The azimuth control box contains a variable frequency drive (VFD).  This is a programmable device that allows us to smoothly accelerate the dome to a maximum velocity typically 1.5x or faster than the standard drive system.  The VFD has multiple speed settings so we can micro-creep the dome while tracking the telescope.

We replace the dome azimuth drive motors with 3-phase motors that operate with the VFD (one motor for domes 5.0m or 16ft 6in and smaller, two motors for domes 5.6 m  18ft 6in and larger). The new motors are 30% more powerful than the original motors and are very efficient.

We typically achieve pointing to better than  0.1 degrees.  This is a positional error of less than about 1 cm on a small dome.  Our customers are surprised that the characteristic sound of the dome rotating is dramatically changed.  It now sounds like a subway train rapidly accelerating away and the whole system is exceptionally smooth and quiet.

The ACE SmartDome has two encoding options.  One uses an incremental encoder.  When power is lost the dome must be sent home.  The other uses a (more expensive) absolute encoder option that never needs to be homed.  95% of our clients elect the incremental encoder for two reasons.  First, the dome controller can be plugged into a small UPS (Uninterruptable Power Supply, or battery backup).  This prevents positional information being lost and it also protects the equipment in general from power surges.  Second, most clients send the dome to the HOME position when not in use.  The positional information is automatically updated after a power loss when at home.

Retrofitting existing Ash domes

We also specialize in retrofitting existing Ash domes.  We can convert the Ash REA style door (the latched up-and-over model) to the Ash REB style door (hinged dropout door model).  We can install an electric winch system for the smaller domes and install a hydraulic control for the larger domes.  Additional services include replacing the azimuth weather seal and installing electrical conductor bars. 

ACE SmartDome software

ASCOM Our high-level software application complements the most versatile and sophisticated controller available.  It is fully ASCOM compliant and it has additional features such as automatic closure due to system failures or poor environmental conditions.

Installing the ACE SmartDome software automatically installs the ASCOM drivers.  The system is very easy to set up and use with TheSkyX, DC-3 dreams ACP software, Maxim-DL and all other ASCOM compatible software.

 There are three icons for operating the shutter doors.  They represent fully closed, open with dropout closed, and both doors fully opened. A green check appears when the dome is in the state that matches the icon.  It is possible to leave the dropout flap up in windy conditions.  When the dropout is disabled a red X appears over the dropout icon.

A password protected engineering setup allows the advanced (or authorized) user to examine and change system parameters to optimize dome performance.

As part of the professional installation by ACE staff we provide basic training on the use of the software. We can also offer services to integrate the dome with the telescope by setting up ASCOM.