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CDK700 Observatory System

SKU# 700101Q

Price: $195,000.00


*Price is based on PlaneWave’s Pricing Policy

Enjoy exceptional performance for astrophotography, research, or visual observing with the CDK700!

  • 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).


Comes with fused silica mirrors on all CDK and RC models    

The CDK700 is a complete observatory class telescope and direct-drive alt-azimuth mounting system, designed and engineered by PlaneWave. With a 70 mm image circle, the CDK700 is designed to excel at imaging on large format CCD cameras. The optical system utilizes a Nasmyth focus through both altitude bearings allowing your camera or eyepiece to remain at a fixed height while holding heavy instruments without needing to rebalance the optical tube assembly.

Instrumentation can be installed on both sides of the fork mount and easily accessed using the included rotating tertiary mirror system. With direct-drive motors, high resolution encoders, and zero backlash or periodic error, the CDK700 set the standard for commercially produced research telescopes.

CDK700 Features

  • Pinpoint stars out to a 70mm image circle
  • Ultra-low thermal expansion fused silica optics
  • Dual Nasmyth focus, allowing simultaneous mounting of two instruments or easy switching between visual and imaging use
  • Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope
  • High resolution encoders on each axis for precise positioning
  • Zero backlash
  • Zero periodic error
  • PointXP mount modeling software
  • Field de-rotator / rotational field framing

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 is that the stars will be pinpoints from the center of the field of view out to the corner of the field of view.

Learn more about our technology here.



Optical System

Optical Design Corrected Dall-Kirkham (CDK)
Aperture 700 mm (27.56 in.)
Focal Length 4540 mm
Focal ratio f/6.5
Central Obstruction 47% of the Primary Mirror
Back Focus from Mounting Surface 309 mm (12.2 inch)
Weight 1,200 lbs (544 kg)
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).
Focus Position  Nasmyth Focus
Image Scale 22 microns per second
Fully Baffled Field 60 mm
Optimal Field of View 70 mm (0.68 degrees)

Mechanical Structure

Fork Assembly Single piece U-shaped fork arm assembly for maximum stiffness
Azimuth Bearing 20-in. diameter thrust bearing
Altitude Bearing 2 x 8.5 in. 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. MaxIm DL is required for camera control when building a pointing model within our PWI2 software.

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 arcseconds)

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)

NOTE: All specifications and dimensions are subject to change.   

Included Items

Included Items

Heating elements for dew prevention The heating pads on the primary and secondary mirror require the 600195 Delta-T controller sold separately
OTA Cover To protect the primary mirror and inside of the optical tube
Flashdrive Contains software and instructions for collimation and spacing the primary to secondary mirror
EFA Kit and IRF90 Port one includes an IRF90 and EFA kit for focusing and derotating within PWI2 software and also relaying mirror temperature data back to the control computer.




For warranty information please check our Standard Warranty Page.