top of page

Control of the dome

The general scheme of operation of the control of the dome is as follows:



Between the computer and the dome there is about 15m, so direct communications with USB are not possible. To fix it, I used the ICRON 2204, a 4-port USB 2.0 extender. The internal unit is connected to the computer via USB and to the external unit with an Ethernet cable. The external unit allows adding to the 4 ports hubs and having remote up to 14 USB devices. The solution works correctly, although it gives problems with some CCD cameras that are powered through the USB and have a high consumption. With low-power cameras or cameras with external power, works well.


I use to connect, depending of the type of job some of these devices:


  • Camera SBIG ST8XME

  • Camera QHY Img2 Pro

  • Camera Canon 60Da

  • Camera Startlight Xpress

  • MoonLite focuser

  • Homemade Photometer

Always connected:

  • MaxDome II for dome control

  • EQ8 mount

  • ON / OFF control and remote start

  • Bluetooth for EQ8 Joystick

All these devices are connected with a single cable between the computer and the dome, which is a very practical solution.

The computer is connected directly (these devices are not next to the dome but next to the computer) the weather station and a GPS.


In the photo, the remote Incron is used to send all the USBs from the dome to the computer with only an Ethernet cable.

Also two USB Hubs are observed since the 4 USB ports of the Icron are insufficient for the number of equipment of the observatory.

An uninterrupted power supply (UPS) is used to power the telescope, cameras and control system. The rotation motor, however, is fed directly from the network without going through the UPS. The idea is that if there is a general power interruption, the power failure has no consequences. For example, if the mount fails the feeding, it is necessary to do later a series of operations to recover the alignment that are quite tedious. With the UPS we avoid this kind of problems.

The UPS was disassembled from its original box (not sealed) and mounted in a watertight cabinet.

An ADAM 4055 was installed in the same cabinet, which has 16 digital outputs. Of the 16, I use only 8 that each attack a relay to be able to make a turn off or turn on 4 turn circuits of 230VAC. The ADAM 4055 has an RS485 output, and with an RS485 to USB converter, it is connected to the ICRON and controlled from the PC with a simple program that basically allows each circuit to be turned on and off independently.


The control of the telescope, dome and weather station is done by ACP Observatory Control Software of DC3 Dreams. This software, really powerful and flexible, allows me to make series of astrophotographs and photometry, allowing to plan if you want several objectives throughout the night.

The software has utilities to automate the flats, dark, bias. Astrometry is really powerful and in practice you forget any pointing process, even if the telescope is totally lost, it solves perfectly. The software handles the movement of the slave dome to the telescope, and is responsible for automatically closing the dome if the weather station sends the information of unsafe time.

ACP Observatory Control in turn uses Maxim DL to control the camera and Autofocus to focus.

As a planetarium I use TheSkyPro.

A description of how the ACP software works:

bottom of page