Optional switches can be installed to control operation past the meridian and for homing. All mounts will be drilled and tapped to accept this option. You can either order the mount with the limit switches installed by Astro-Physics (part # 36LSS) or it can be added as an upgrade later and installed by the customer (part # 36LSSKIT).
The limit switch/homing switch option can be configured several different ways, depending on the needs of the user. This flexibility is in keeping with our modular philosophy. Not everyone will need all the functions of these switches, so we will leave it up to the user to choose how the switches should be configured.
Simple Limit and Home Switch Option
The simplest option is to install the switches and wire the normally closed contacts directly into your power line. A simple user activated manual override switch can then be wired in parallel with the limit switch. This switch is operated by the user to re-power the mount so that the scope can be safely slewed back to the proper side of the mount via a Go-To command. The switch module also contains the homing switch, which can be used to determine when the mount has reached the home position (basically pointing the scope to the eastern horizon). There is one homing switch for the RA and one for Dec. The limit switches are only for RA (the Dec must be allowed to go 360 degrees in order to cover the entire sky). In order to use the homing switch, the user would need to wire it into his own circuit, if the optional control circuit is not purchased. The way it works is then very simple. When the scope passes the meridian, the limit switch activates and simply cuts power to the servo. This stops the mount from tracking or slewing further, protecting the scope from potentially banging into the pier. The normally open contact can be wired to a 12 volt bulb or buzzer, which can alert the user that the mount has reached the maximum limits and is now stopped. This method of cutting power directly to the mount does not require any more electronic circuitry, and is the most foolproof way to stop the mount from exceeding the movement limits. It is not affected by lightning strikes, power surges or computer failures and will override any false commands from any outside source.
Installation included if purchased with the mount. May be purchased at a later date to be installed by the customer.
36LSS Limit and Homing Switch System for 3600GTO (ordered at time of manufacture)
36LSSKIT Limit and Homing Switch System for 3600GTO (ordered as an upgrade)