Mathis Instruments Fork Mount

Part#: 600500

Price: $27,800.00

Mathis Instruments offers three basic models of fork mounts: MI-500, MI-750, and Mi-1000. Planewave offers hybrid models that feature the larger forks for each polar base. These model are intended for those needing larger swing-through, greater arm separation for tube assemblies and better vibration surpression. The hybrid model are the MI-500 polar base with MI-750 fork, the M-750 polar base with a MI-1000 fork, and the MI-1000 polar base with a MI-1250 fork.

CDK20 and the MI750 Fork Mount  $64,600

(Includes: CDK20 telescope,  MI750 Fork Mount, and custom parts for the MI750 to mount to PlaneWave

Item Item Number Price
CDK20 Telescope 200103 $35,000
MI750 Mount (with MI1000 fork arms)
600500 $27,800
Hedrick Focuser 200340 $1,000
EFA (Focuser, Fan Control) Kit 200901 $800
Custom parts for the MI750 to mount to PlaneWave 600509 $1,000
TOTAL   $64,600



Sidereal Technology Servo II

Mathis mounts are normally supplied with the Servo II computer control from Sidereal Technology (SiTech). This is the standard computer control package installed with each mount and must be used when fitting the mount with Planewave HiRes Axis encoders.  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

In addition to the SiTech control system, all Mathis mounts can also be controlled with Astrophysics GTO Computer Control  or Bisque Telescope Control System (TCS) for an additional charge.


CDK24 / MI1000 High Precision Package - $114,060

Planewave also provides a high precision package for all Mathis Fork mounts that includes longer, sturdier fork arms attached to each base (1250 forks on Mi1000 base shown below).  Hi-res axis encoder are also attached on both RA and Dec and is controlled by SiTech control system software. Bronze RA gear upgrade available for MI500 and MI750 (comes standard with MI1000).

CDK24 on MI1000 Mount

Item Item Number Price
CDK24 Telescope 240103 $52,500
IRF90 Rotating Focuser 600180 4,500
EFA Kit – Control Focuser, Fan, Heater 240901 1,000
MI1000/1250 Mount 600520 $42,800
Hi-Res Axis Encoders 600508 $7,500
SiTech Control Configuration Charge 600536 $3,500
Homing Sensor & Mask 600505 $1,260
Custom dovetail clamps for the MI1000. 600510 $1,000
TOTAL   $114,060



Type Fork Mount (Observatory Class)
Weight 260 lbs (118 Kg)
Max. Load Capacity 180 lbs (82 Kg)
Latitude Range 28 to 52 degrees
Azimuth Range 8 degrees
Finish Powder coated sand castings


RA Gear 15.2", 450 tooth, aluminum worm wheel (optional bronze gear available)
Dec Gear 12.2", 360 tooth, aluminum worm wheel
RA and Dec Axes 120mm (4.724") aluminum shaft
DEC Axis 100mm (3.937") aluminum shaft
More Info Precision Worm Drive


Base Diameter 14 inches
Base Height 21 inches
Base Weight 140 lbs (64 Kg)
Fork Flange Diameter 8 inches
Axes to bottom of fork 23 inches
Swing Through (from focuser) Swing Through (from focuser) aprox. 10 inches
Dovetail to Dovetail Distance Dovetail to Dovetail Distance ~26.7" (varies slightly)
Dovetail CAD Drawing Dovetail CAD Drawing(PDF)

 Type MI 750 Fork Mount
 Weight 260 lbs (118 Kg)yellow
 Max. Load Capacity 180 lbs (82 Kg)
 Latitude Range  28 to 52 degrees
 Azimuth Range  8 degrees
 Finish Powder coated sand castings
 Base Diameter 14 inches
 Base Height 21 inches
 Base Weight 140 lbs (64 Kg)
 Fork Flange Diameter 8 inches
 Axes to bottom of fork 23 inches
 Swing Through (from focuser)  aprox. 10 inches
 Dovetail to Dovetail Distance  ~26.7" (varies slightly)
 Dovetail CAD Drawing
 RA Gear 15.2", 450 tooth, aluminum worm wheel (optional bronze gear available)
 DEC Gear  12.2", 360 tooth, aluminum worm wheel
 RA Axis 120mm (4.724") aluminum shaft
 DEC Axis  100mm (3.937") aluminum shaft
 More Info  Precision Worm Drive