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PlaneWave Instruments brings a fully automated observatory class telescope to the market with the CDK700, a 0.7 meter Alt-Az telescope system. We are combining the revolutionary CDK optical design that founded PlaneWave Instruments with an innovative direct-drive alt/az mount technology that sets a new standard for small observatory telescopes.


  • f/6.5 and 4540mm focal length providing pinpoint stars across a 70mm image circle.
  • No coma, no off-axis astigmatism, and no field curvature.
  • Compact Alt/Az design with dual Nasmyth ports allowing multiple instrumentation payloads to be installed on the telescope.
  • Integrated direct drive mount with optical encoders, zero periodic error, zero backlash, and minimal maintenance due to the lack of gears.
  • Slew speeds up to 50 degrees/sec for satellite tracking and fast target acquisition.
  • Fast 1 day installation and on-sky taking images that same night (weather dependent).



An alt/az mount is inherently more stable than an equatorial mount since there is no cantilevered mass, nor are there any large protruding counterweights to create a dangerous hazard in a public observatory. An alt/az telescope is also considerably more compact than its equatorial counterpart, allowing a larger telescope to fit in a smaller enclosure. The mass it takes to make a rigid alt/az mount is substantially less, leading to cost savings. Unlike German Equatorial mounts, there are no meridian flips to deal with. You can image from horizon to horizon continuously if desired. Alt/Az is more intuitive to use and no polar alignment is needed. Besides, it is the way the professionals do it!


Benefits of Nasmyth Focus
The Nasmyth Focus is along the altitude axis so there are virtually no balancing issue as you change out equipment. Eyepieces remain at a constant wheelchair-accessible height, greatly simplifying access to the telescope for public observatories. The rotating tertiary mirror allows you to switch from one Nasmyth port to the other in just seconds, allowing observers to easily transition between imaging and visual use.

Rotating Tertiary Mirror
The CDK700 includes an integrated rotator for the tertiary mirror, with magnetic locks to position the mirror precisely for either Nasmyth focus position. The rotator can move from one port to the other in under 10 seconds. Checkout the tertiary mirror video here.

Direct drive motors and encoders
Direct Drive motors mean that there are no gears to cause backlash and periodic error. With high-resolution encoders providing the feedback for the direct drive motors, not only will the telescope track without periodic error or have any backlash at all, but the mount will be able to counter against wind gusts. The direct drive motors can move the telescope at incredible speeds for tracking satellites or just to minimize target acquisition time.

CDK Optical Design:
The CDK (Corrected Dall-Kirkham) Optical Design is an innovative solution for unsurpassed astroimaging quality at an affordable price. The CDK telescope design provides excellent imaging with large format CCD cameras while remaining superb for visual use. The CDK design far exceeds the off-axis performance of most commercial telescope designs including the Ritchey-Chrétien design.

Our design produces a flat, coma free and astigmatic free field of view. Since the secondary mirror is spherical, centering is very forgiving. This means it is easy to get the telescope optics aligned for optimum performance, which is not the case for most high-end astrographs. The end result at the image plane of the CDK design is no off-axis coma, no off-axis astigmatism, and a perfectly flat field all the way out to the edge of a 70mm image circle.  All this means that the stars will be pinpoints from the center of the field of view out to the corner of the field of view.


PlaneWave CDK700 Observatory System

Sales Tax Included
  • Optical System

    Optical Design Corrected Dall-Kirkham (CDK)
    Aperture 700 mm (27.56 inch)
    Focal Length 4540 mm
    Focal ratio 6.5
    Central Obstruction 47% of the Primary Mirror Diameter
    Back Focus 309 mm (12.2 inch) from Mounting Surface
    Weight 1,200 lbs
    Optical Tube Dual truss structure with Nasmyth focus
    Optical Performance 1.8 micron RMS spots [25mm on-axis] (400 to 900nm) 4.4 micron RMS spots [21mm off-axis] (400 to 900nm) 6.8 micron RMS spots [35mm off-axis] (400 to 900nm) Spot Diagram.
    Dimensions 93.73″ H x 43.25″ W x 39″ D (Drawing here).
    Optimal Field of View 70mm image circle (0.86 degrees)
    Focus Position Nasmyth Focus
    Fully Baffled Field 60 mm
    Image Scale 22 microns per arcsecond

    Mechanical Structure

    Fork Assembly Single piece U shaped fork arm assembly for maximum stiffness
    Azimuth Bearing 20 inch diameter thrust bearing
    Altitude Bearing 2 x 8.5 inch OD ball bearings
    Optical Tube Dual truss structure with Nasmyth focus

    Motion Control

    Motor Control Industrial grade Parker brushless motor control system and built in electronics
    Azimuth Motor Direct Drive 3 Phase Axial-Flux Torque Motor
    Altitude Motor Direct Drive 3 Phase Axial-Flux Torque Motor
    Encoder – Azimuth and Altitude 10 inch disk built into the azimuth and altitude axes with stainless steel encoder tape on the circumference with reader yields 16 million counts per revolution of the telescope. This translates to about 0.08 arcsecond resolution.
    Motor Torque Approximately 30 ft-lbs continuous; 60 ft-lbs peak
    Drive Electronics Capable of controlling up to 4 high speed encoders, limit switch inputs, homing switch inputs, controls two additional motors for accessories, two brake outputs and 16 digital and 2 analog inputs
    Telescope Control Software Incorporates PointXP mount modeling software by Dave Rowe All ASCOM compatible.

    System Performance

    Pointing Accuracy 10 arcsecond RMS with PointXP Model
    Pointing Precision 2 arcsecond
    Tracking Accuracy <1 arcsecond error over 10 minute period
    System Natural Frequency 10 Hz or greater
    Field De-Rotator Accuracy 3 microns of peak to peak error at 35mm off-axis over 1 hour of tracking (18 arc sec)

    Primary Mirror

    Radius of Curvature 4115mm
    Optical Diameter 700 mm (27.56 inch)
    Outer Diameter 714.38 mm (28.125 inch)
    Core Diameter 203mm (8 inch)
    Material Fused silica (quartz)
    Edge Thickness 2.25 inch
    Cell 18 point

    Secondary Mirror

    Radius of curvature 2961 mm
    Thickness 25 mm
    Optical Diameter 312.4 mm (12.3 inches)
    Outer Diameter 317.5 mm (12.5 inches)
    Material Fused silica (quartz)
    Cell 3 point RTV

    Tertiary Mirror

    Optical Major Diameter 152.4 mm
    Thickness 25 mm
    Material Fused silica (quartz)
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