PlaneWave - CDK700 Observatory System

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The PlaneWave Instruments CDK700 is a research grade observatory system with 700mm Corrected Dall Kirkham optics and a precision Alt-Azimuth mount. 

Made for quick installation, you can be up and running in as little as one day on delivery. 

The CDK700 is a 700mm CDK f/6.5 instrument with a 70mm image circle. 

The direct drive mount with optical encoders provides high precision and accuracy with zero backlash, and no periodic error with very little required maintenance thanks to the lack of gears. 

Slew speeds of up to 50 degrees per second for satellite tracking and fast target acquisition.  

If you choose to place an order for this item, you will be contacted for crating and shipping fee information and options.  To receive a quote contact us at [email protected]

Planewave Instruments CDK700 Observatory System

The Planewave Instruments CDK700 is a 700mm observatory-class Corrected Dall Kirkham telescope featuring a direct drive altitude-azimuth (Alt-Az) mounting system designed and engineered by PlaneWave. With a diffraction-limited 100mm image circle, the CDK700 is designed to excel at imaging on the largest format CCD cameras available today. Light-weighted optics are made of zero expansion fused silica materials for excellent thermal stability and maximum throughput. The dual Nasmyth ports allow two instruments to be installed simultaneously, and a computer-controlled M3 mirror allows either instrument to be remotely selected in seconds.

CDK700 Features: 

  • Pinpoint stars over a 100mm image circle (1 degree)
  • Dual Nasmyth focus ports, allowing simultaneous mounting of two instruments and easy switching between imaging and visual use.
  • Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope
  • High-resolution absolute encoders on each axis for precise positioning
  • Zero backlash
  • Zero periodic error
  • PointXP mount modeling software
  • Integrated field de-rotator / rotational field framing
  • Integrated primary mirror shutter cover

Planewave Instruments Observatory System Mount

Alt-Az mounts are the choice for most modern professional observatories. 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 required to make a rigid Alt-Az mount is substantially less, leading to substantial cost savings. Unlike German Equatorial mounts, there are no meridian flips to deal with; you can image continuously from horizon to horizon if desired. With no polar alignment required, the Alt-Az mount is far more intuitive to use than a German Equatorial mount.

CDK700 700mm Corrected Dall Kirkham Optics

PlaneWave CDK700s are deployed around the world at various institutions such as: Caltech, Harvard, Penn State, University of New South Wales, Simon Frasier University, University of Montana and University of Hamburg, and many more.

The CDK (Corrected Dall-Kirkham) Optical Design is an innovative solution for unsurpassed scientific investigation, visual observing and astro-imaging at an affordable price. It has excellent performance with large format CCD cameras, far exceeding the off-axis performance of most commercial telescope designs, including the uncorrected Ritchey-Chrétien.

Planewave's design produces a flat, coma-free and astigmatic-free field of view. Since the secondary mirror is spherical, centering is very forgiving, making it easy to align the telescope optics for optimum performance. The end result at the image plane is no off-axis coma, no off-axis astigmatism, and a perfectly flat field to the edge of a 70mm image circle. The stars will be pinpoints from the center to the corner of the field of view.

Fused Silica Optics and Mirror Technologies

By utilizing fused silica optical glass Planewave's CDK telescopes take advantage of a thermal expansion rate that is naturally 6 times lower than typical Borosilicate "Pyrex" optical glass.   Planewave's optics retain their shape through long imaging sessions and require less frequent adjustments to focus due to temperature changes for consistent performance. 

A rotating tertiary mirror locks into position using a magnetic locking system for precision positioning in either Nasmyth port, to ensure perfect focus when switching instruments.  Ports can be switched in less than 10 seconds.  Nasmyth focus is maintained at the altitude axis, eliminating the need to rebalance the telescope when switching from port to port regardless of what instruments are in use.  Eyepieces also remain a constant height making observing and monitoring easy and aiding ease of access for public observing.  A computer controlled M3 mirror selects each port quickly, reducing the time needed for transitions.  Easily move from observing to imaging. 

To protect the primary mirror from dust and moisture an integrated four shutter automated system can be controlled with Planewave's PWI software and is included.  

Direct Drive Motors & Encoders

Direct Drive motors and absolute on-axis encoders eliminate the need for reduction gears, thereby eliminating 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 and backlash, the mount will also counter wind gusts with precise servo feedback. The direct drive motors can move the telescope at incredible speeds for tracking satellites or just to minimize target acquisition time.


Optical System


Optical Design

Corrected Dall-Kirkham CDK


700mm (27.56 inches)

Focal Length


Focal Ratio


Central Obstruction

47% of the Primary Mirror Diameter

Back Focus

309mm (12.2 inches)


1200 lbs. 

Optical Tube

Dual Truss Structure with Nasmyth Focus Ports

Optical Performance

1.8 micron RMS spots on-axis (25mm on-axis), 4.4 micron RMS spots (21mm off-axis 400 to 900 nm), 6.8 micron RMS spots (35mm off-axis) (400-900nm)


93.73" H x 43.25" W x 39" D

Optimal Field of View

70mm (0.68 degrees)

Focus Position

Nasmyth Focus

Image Scale

22 micron per second

Fully Baffled Field



Mechanical Structure


Fork Assembly Single Piece U Shaped Fork Arm Assembly For Maximum Stiffness


Azimuth Bearing

20 inch diameter thrust bearings

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
Motor - AZ and Altitude Direct Drive 3 Phase Axial-Flux Torque Motor
Encoder - AZ and Altitude Absolute encoder with a resolution of 0.005 arcseconds (268 million counts per revolution)
Motor Torque Approx. 30 ft lbs continuous; 60 ft lbs peak
Drive Electronics Controls the altitude and azimuth motors and encoders, 2 direct drive de-rotators with absolute encoders, 4 fans zones, 3 dew heater zones, two focusers, an array of temperature sensors, M3 port selector, primary mirror covers and magnetic axis deceleration
Telescope Control Software PlaneWave Interface 4 (PWI4) Software. Incorporates PointXP mount modeling software and All Sky PlateSolve, both by Dave Rowe. Also includes automatic focusing, dew heater control, primary mirror cover control, dome control and provides HTTP and ASCOM control interfaces. Linux and Windows compatible. MaxIm DL is required for camera control when building a pointing model within PWI4 software.


System Performance


Pointing Accuracy Better than 10 arcsecond RMS with PointXP Model
Pointing Precision 2 arcseconds at sidereal velocity
Tracking Accuracy < 1 arcsecond over a 10 minute period at sidereal velocity
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 700mm (27.56 inches)
Outer Diameter 714.38mm (28.125 inches)
Core Diameter 203mm (8 inch)
Material Fused Silica Quartz
Edge Thickness 2.25 inches
Cell 18 Point


Secondary Mirror

Radius of Curvature 2961mm
Optical DIameter 312.4mm (12.3 inches)
Material Fused Silica Quartz
Outer Diameter 317.5mm (12.5 inches)
Thickness 25mm
Cell 3 Point RTV



Tertiary Mirror


Optical Major Diameter 152.4mm
Thickness 25mm
Material  Fused Silica Quartz


** All specifications are subject to change.

Shipping Information

The PW1000 is an oversize item that must be shipped via freight delivery.  You will be quoted final shipping rates upon ordering.  If you require a quote prior to ordering please contact us at [email protected].  

More Information
Brand PlaneWave Instruments
Free Shipping Does Not Qualify for Free Shipping
Aperture 700mm
Case Included No
Focal Length 4540mm
Focal Ratio F/6.5
Optical Tube Material Truss
Accessory Tray Included? No
Adjustable Legs? No
Includes Autoguide Port Yes
Included Software PWI4 and PointXP
Periodic Error Correction No
In The Box
  • CDK700 Optical Tube
  • Fork Arm AZ Mount
  • Built In Heating Pads on Primary and Secondary requires 600195 Delta T Heater, Sold Separately
  • OTA Cover
  • Flashdrive with all instructions and software
  • EFA Kit and IRF90 with mirror temperature relay
  • FeatherTouch Focuser and Adapter
  • CDK700 Optical Tube
  • Fork Arm AZ Mount
  • Built In Heating Pads on Primary and Secondary requires 600195 Delta T Heater, Sold Separately
  • OTA Cover
  • Flashdrive with all instructions and software
  • EFA Kit and IRF90 with mirror temperature relay
  • FeatherTouch Focuser and Adapter
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