Mathis Instruments Homing Masks & Sensors for Servo II
The Mathis Instruments Homing Masks & Sensors for Servo II enable telecope control from a remote location. Homing disks are intalled on the RA and declination axes. A sensor on each axis records the home zero position.
Sidereal Technology Servo II
The MI-500, MI-750, and MI-1000 mounts are normally supplied with the Servo II computer control from Sidereal Technology. This is the standard computer control package we ship with each mount. This control has a rich set of features including the following:
- Can be used with a variety of DC servo motors including Pittman and Maxon
- Uses high quality industrial Turch cabling and connectors
- Provides continuous tracking and full “GoTo: capability
- Supports adjustable drive rates for tracking any solar system object
- Outputs 4 amps per axis at 24 volts using any 12 to 24 volts DC power supply
- Uses separate cables for encoder signals and power lines to the motor
- Features hardware sensors on the worm shaft for PEC correction
- Supports homing using sensors on each axis for remote operation
- Offers secondary high resolution axis encoders for arc second tracking and pointing
- ACOM capatible for use with most PC software
The Servo II control supports German and equatorial fork mounts, as well as altazimuth mounts. It has an open architecture that gives access to nearly every motor and control parameter. Using Pittman 9000 or 14000 series motors, the Servo II provides a motor encoder resolution of 0.10 arcseconds per count.
The Servo II control features a PEC sensor on the RA worm shaft that records the phase of the worm rotation. A periodic error profile can be applied since the phase of the worm rotation is always known, even after powering down the control. The PEC does not depend on timing the rotation of the worm. Rather the worm phase is determined by the sensor on the worm shaft.
The Servo II also supports mount homing. The feature enables telecope control from a remote location. Homing disks are intalled on the RA and declination axes. A sensor on each axis records the home zero position.
When the mount and control are first turned on, a command is given to find the home position. The servo motors move each axis, searching for the zero position as measured by they home sensor. Once located, the position of the telescope in local altazimuth coordinates is known. From the local sidereal time and the longitude and latitude of the observatory, the position of the telescope in equatorial coordinates can be calculated. The observer knows where the telescope is pointed in the sky, whether in the observatory or on the other side of the world. The Servo II control is ASCOM capatible, so it can be used with many popular astronomy programs to control your telescope. Using your laptop, you can position the telescope, center an image and control the tracking rate, and then park the telescope at the end of the night.
The Servo II support high resolution encoders.Ring encoders are installed on each axis. An electronic read-head record axis motion independent of any errors in the motor gear head, the worm gear, and timing pulleys. These ring encoders provide .10 arc second resolution on each axis. They have typical error profiles of plus/minus 4 arc seconds over 360 degree (pointing error over the entire sky) and short term errors (tracking errors) of plus/minus .20 arc seconds. Even these small errors can be modelled and reduced.
The encoders (British Renishaw encoder rings) are integrated into the mount during construction. The components that support the encoder rings are made of thick stainless steel to provide a thermal barrier between the encoder ring and the large aluminum components in the mount.
This Servo II control requires a 12-28 volt power supply with a minimum output of 5 amps. A variable voltage supply is recommened.