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Planewave CDK500 Observatory System

SKU 200130Q
Original price $56,000.00 - Original price $56,000.00
Original price
$56,000.00 - $56,000.00
Current price $56,000.00

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Enjoy exceptional optical and tracking performance for astrophotography, or research, with the CDK500 package! Includes a CDK20 optical tube and L-500 mount.

The PlaneWave Instruments CDK20 is a 20 inch (0.51 m) f/6.8 Corrected Dall-Kirkham Astrograph telescope. The CDK20 has a dual carbon-fiber truss design, with 3 cooling fans ejecting air from the back of the telescope. The CDK20 covers a 52 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 140 lbs (64 kg) and comes standard with a back plate retaining ring ready to accept the focuser of your choice.

CDK20 optical tube:

  • f/6.8 and 3454mm focal length

  • No coma, no off-axis astigmatism, and no field curvature

  • Pinpoint stars across a 70mm image circle.

  • Rock solid fused silica mirrors with low thermal expansion.

  • Carbon fiber optical tube assembly for rigidity and fast cooling.Simple secondary mirror collimation thanks to the fixed primary mirror.

L-500 direct drive mount:
  • 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.

  • Sidereal tracking accuracy of < 0.30 arcseconds RMS over 5 minutes.

  • High resolution optical encoders on both axes for precision feedback.

  • Can be installed in either equatorial, or alt/az configuration.

  • Includes PWI4 software (ASCOM compliant) for mount control.

    All CDK20 telescopes come with fused silica primary and secondary mirrors. 

    The L-Series combines versatility, simplicity and affordability by combining all the technology of our Observatory class telescopes into a compact stand-alone mount.  In its Alt/Az configuration it is 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, and no  large protruding counterweights to create a dangerous hazard in a public observatory. Alt/Az is more intuitive to use and no polar alignment is needed. Besides, it is the way the pros do it!

    L-Series Mount Features
    • Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope

    • Slew speeds up to 50 degrees per second

    • High resolution encoders on each axis for precise positioning

    • Zero backlash

    • Zero periodic error

    • PointXP mount modeling software

    • Enclosed electronics

      • Through the mount cabling

      Direct drive motors and encoders

      Direct Drive motors and on-axis encoders eliminate the need for  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.

      Incredible Slew Speed

      The direct drive motors can move the telescope at speeds up to 50 degrees per second for tracking satellites or just to minimize target acquisition time.

      Dual mounting bracket

      PlaneWave style mounting bracket to hold CDK17/20 onto inside of fork arm with additional option of mounting a scope on the outside of the fork arm. Optional dovetail clamp required.

      Azimuth dovetail balance system

      For precise center of gravity balance whether in Alt-Az or Equatorial configuration

      Through the mount cabling

      Access panels in the fork arm and azimuth axis allow for camera equipment cabling through the inside of the mount.

      Proven CDK700/PW1000 Technology

      The L-Series uses the same proven technology as the CDK700 and 1-Meter PW1000 which are being used in Universities round the world.

      CDK-500 + Core Accessories

      Item Number



      200130Q CDK-500 (CDK20 / L-500) $47,000
      600180 IRF90 Rotating Focuser $  4,500
      200901 EFA, Focuser Accessory Control $  800
      Total $52,300

      Mount System

      Type Alt-Azimuth / Equatorial Direct Drive Mount
      Weight 257 lbs (100 kg)
      Component Weights Azimuth Base – 121 lbs, Fork Arm – 136 lbs
      Max. Load Capacity 200 lbs (91 kg)
      Latitude Range 0 to 90 degrees, Northern and Southern hemispheres
      Cable Management Equipment cables can be wired through mount

      Control System

      Control Electronics PlaneWave Interface dual axis telescope control
      User Interface PlaneWave Interface 4 (PWI4) Control Software with integrated PointXP mount modeling software
      Homing Sensors Home position sensors are included allowing the mount can find its home position on power up.
      Slew Rate 20 degrees per second (standard); 50 degrees per second (maximum), both axes
      Power Requirement Accepts 120 VAC. Supplied with 12VDC 15A Regulated Power Adapter

      Optical System

      Aperture 20 inch (508 mm)
      Focal Length 3454 mm (135.98 inch)
      Focal ratio F/6.8
      Central Obstruction 39% of the Primary Mirror Diameter
      Back Focus from Racked in Focuser 5.8 inch (147 mm)
      Weight 140 lbs (63.5 kg)

      Motion Control

      Motor Control Industrial grade brushless motor control system and built in electronics
      Motor – Azimuth and Altitude Direct Drive 3 Phase Axial-Flux Torque Motors
      Encoder – Azimuth and Altitude 152mm stainless steel encoder ring with reader built into the azimuth and altitude axes. 18,880,000 counts per revolution (0.069 arcsecond resolution).
      Motor Torque Approximately 20 ft-lbs continuous; 50 ft-lbs peak
      Drive Electronics Industrial grade, off-the-shelf brushless motor drives for each axis with custom designed interface card
      Telescope Control Software PlaneWave Interface (PWI4). Incorporates PointXP mount modeling software by Dave Rowe. Provides HTTP and ASCOM control interfaces.

      System Performance

      Pointing Accuracy <10 arcsecond RMS with PointXP Model
      Pointing Precision

      2 arcseconds at sidereal velocity

      Tracking Accuracy

      < 0.3 arcseconds over a 5 minute period at sidereal velocity

      System Natural Frequency 10 Hz or greater

      L-500 Pier Interface Drawing

      L-500 Mount Dimensions

      L500/600 Mount Instructions

      PlaneWave Interface 4 Software User Manual_V15 1.7.2021

      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
      Hardware Six 1/2-13 x 1 1/4″ socket head cap screws to bolt the mount to the pier, or wedge


      Six 1/2-13 washers

      One extended length shoulder bolt for RA axis to EQ wedge alignment

      One 16′ USB cable To connect the mount to the observatory control computer
      One 120VAC power cable To provide power to the mount
      Standard Allen Key set For tightening bolts used on the mount
      Flashdrive Contains PWI4 software for mount control and instructions for installation
      Gamepad Used for control of the mount tracking speeds for visual observing
      Recommended Accessories

      Reducer .66x CDK20 (200166)

      Mounting Bracket for Finderscopes  (125360)

      Finderscope and Mounting Bracket (200985)

      Visual Adapter – CDK20 (200399)

      Delta T Heater Part (240901)

      Hendrick Focuser (200340)

      IRF90 – Integrated Rotating Focuser (600180)

      EFA kit Electronic Focuser (EFA)

      Light Shroud CDK20 (200970)

      Dovetail Clamp CDK20 (200919)

      Piggyback Dovetail Bars (200990)

      Portable Rolling for Pier Mounts (600128)

      Equatorial Wedge, L-500/L-600 Mount (600560)