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PlaneWave - 17" CDK17 Corrected Dall-Kirkham Carbon Fiber Truss Telescope

Model#: 170101

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Availability: In stock


Manufactured by: PlaneWave Instruments


The PlaneWave Instruments CDK17 is a 17 inch (0.43 m) f/6.8 Corrected Dall-Kirkham Astrograph telescope. The CDK17 has a dual carbon-fiber truss design, with 3 cooling fans ejecting air from the back of the telescope, and 4 fans blowing across the boundary layer of the mirror's surface. The CDK17 covers a 70 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 106 lbs (48 kg) and comes standard with a back plate retaining ring ready to accept the focuser of your choice.



Carbon Fiber Truss Design Minimizes thermal expansion which causes focus shift with changes in temperature
Dovetail Expansion Joint Allows for the difference in thermal expansion between carbon fiber and aluminum. The expansion joint allows the aluminum dovetail expand and contract without stressing the carbon fiber lower truss
Cooling Fans Three cooling fans ejecting air from the back of the telescope and four fans blowing across the boundary layer of the mirror surface. This helps the telescope to reach thermal equilibrium quickly. The fans are controlled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.



Diameter 17.5 inch (445 mm)
Aperture 17 inch (432 mm)
Focal ratio f/3.24
Mounting Laser Collimated and Permanently Fixed
Material Precision Annealed Pyrex
Shape Prolate Ellipsoid
Coating Broadband AR Coatings (less than .5% reflected from 400 to 700nm)



Diameter 190 mm (7.48 inch)
Material Precision Annealed Pyrex
Shape Spherical
Coating Broadband AR Coatings (less than .5% reflected from 400 to 700nm)


Ronchi Spacer (600341 & 600343) This spacer sits in place of a focuser and is used for setting the primary to secondary spacing. It has an 1-1/4 inner diameter and may be used with 1-1/4 oculars for collimation
Ronchi Ocular This ocular is a Ronchi screen used for setting the primary to secondary spacing
Primary Mirror Cover The Primary Mirror Cover protects the primary mirror
Planewave Thumb Drive Containing all documentation and software for collimation and spacing
12VDC Power Supply Provides power for the fans (Not included for European Orders)
Wrench Set (5812A35) English Hex Wrenches (European Orders Only)


C/2012 S1 (ISON)


Copyright Tim Stone

Technical Card

  • Imaging telescopes or lenses: Planewave Instruments CDK 17
  • Imaging cameras: Apogee U16M
  • Mounts: Software Bisque Paramount ME
  • Guiding telescopes or lenses: Planewave Instruments CDK 17
  • Guiding cameras: SBIG STi
  • Software: Maxim DL, photoshop
  • Filters: Astrodon E-series 2 L,  Astrodon E-series R,  Astrodon E-series B,  Astrodon E-series G
  • Accessories: Astrodon Monster MOAG
  • Resolution: 1496x1496
  • Dates: Nov. 14, 2013
  • Locations: Sugar Grove Observatory
  • Frames: 45x60"
  • Integration: 0.8 hours
  • Avg. Moon age: 11.25 days
  • Avg. Moon phase: 86.62%


Data acquired by Bob Finnigan and Carl Wenning at the SGO the morning of November 14. The original is more "raw" and the second version is processed to remove stars and enhance color contrast to a degree. The transition from cyanogen-dominated emission to the blue ion tail is clearer in the second version. In the final version, I reprocessed, aligning on the stars rather than the comet, and added the stars back in for a more natural view.

Incidentally, the slight smudge below the tail is a galaxy, PGC 43020 at 13th magnitude.

Astrometry from TheSkyX Pro:

  • Center RA: 12h 46m 09.0s
  • Center Dec: -06° 04' 16.3"
  • Scale: 1.25 arcseconds/pixel
  • Size (pixels): 1763 x 1763
  • Angular Size: 0° 36' 53" x 0° 36' 53"
  • Position Angle: 353° 58' from North
  • RMS: 0.71 (X: 0.52 Y: 0.48)
  • Number of Stars Used in Solution: 112 (99%)
  • FWHM: 5.31 pixels, 6.66 arcseconds


Data acquired at the Sugar Grove Observatory, a facility of Twin City Amateur Astronomers (tcaa.us).




Product Series

The CDK telescope is a brand new optical design invented by Dave Rowe. The goal of the design is to make an affordable astrographic telescope with a large enough imaging plane to take advantage of the large format CCD cameras of today. Most telescope images degrade as you move off-axis from either coma, off-axis astigmatism, or field curvature. The CDK design suffers from none of these problems. The CDK is coma free, has no off-axis astigmatism, and has a flat field. The design is a simple and elegant solution to the problems posed above. The CDK consists of three components: an ellipsoidal primary mirror, a spherical secondary mirror and a lens group. All these components are optimized to work in concert in order to create superb pinpoint stars across the entire 42mm image plane.

Additional Information

Name PlaneWave - 17" CDK17 Corrected Dall-Kirkham Carbon Fiber Truss Telescope
Manufacturer PlaneWave Instruments
Model 170101
Aperture 17 inch (432 mm)
Focal Length 2939 mm (115.71 inch)
Focal Ratio F/6.8
Optical Design Corrected Dall-Kirkham