Dome Automation

The dome is a 5 meter Observa-DOME originally installed 10+ years ago with two AC motors and a lever switch.   In 2002, we added automation to it so that we could control it remotely.  The dome now moves to the correct location whenever the scope slews.  Calculations are made to adjust the location depending on which scope is currently the primary scope.  The dome also moves with the scope as it tracks.

We looked at commercial packages for dome automation and decided to do it ourselves.  Total cost was about $350 for parts, plus lots of labor for program development and installation.  Today there are alternatives for dome automation available with ASCOM that we would probably use if doing the development again.

To the right is a screenshot of the control program.  Turning on "Slave to Dome" causes the dome to move  when the scope slews and  to keep up with scope tracking. 

Astrometric Instruments' SkyWalker system is used for telescope control.  The dome program communicates via SkyWalker to send 12VDC signals to the relay box to control the dome motors.  The dome program also obtains slewing status, azimuth, and altitude from the SkyWalker system.   Below is a picture of the SkyWalker box.  It's also attached to the motor drivers, autoguider,  PC, and a hand paddle.  The hand paddle can be used to move the dome in addition to scope control.  

This  picture shows the original lever switch box and an added relay box on the left.  The relay box contains two relays for dome motor control and a switch on top to switch between PC or lever box control.  The relays are controlled from the SkyWalker.

Here's a picture of one of the AC motors:

The dome program determines the current dome position via a bar code reader pictured on the right.  Notice the red laser beam reading the barcodes.  They were printed on quality paper, laminated, and have 0.5 degree increments from 0 to 359.5.  This positioning method has worked quite well.