Astronomy Specialist





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The PlaneWave Instruments CDK20 Corrected Dall-Kirkham is an innovative telescope for unsurpassed astroimaging, research, or satellite tracking. With rock-solid fused silica mirrors, carbon fibre construction and pinpoint stars across a 52mm image circle, the CDK20 is the capable of capturing the most stunning astrophotographs possible.

The CDK20 is an incredible breakthrough in telescope technology and produces no off-axis coma and no off-axis astigmatism. Additionally, the CDK20 provides a perfectly flat field so your astrophotographs will have stunning clarity from corner to corner of the image without field curvature degrading the photos.

Offering the simplicity of single-mirror collimation, the stray light control of advanced baffles, structural performance created through finite element analysis (FEA), and decades of telescope design experience, the CDK20 is an exceptional diffraction-limited telescope. 

CDK20 users can experience pinpoint stars edge-to-edge and a 52 x 52 arcminute field of view when using large 16803 size camera sensors. When equipment fades into the background and simply performs, the astrophotography experience becomes even more fun and rewarding!


PlaneWave CDK20 optical performance 


  • Carbon fibre tube minimizes thermal expansion, which causes focus shift as temperature changes during an imaging session. Carbon fibre also reaches ambient temperatures quickly and is extremely lightweight and rigid to help ensure excellent imaging data is produced.
  • Dovetail Expansion Joint allows for the difference in thermal expansion between carbon fiber and aluminium. The expansion joint allows the aluminium dovetail to expand and contract without stressing the carbon fiber lower truss.
  • 3D-printed precision positioned, lightweight baffle tubes to minimize vignetting and maximize image contrast. 
  • Delta-T ready - For added dew prevention, the CDK20 is internally wired with polyimide film heater pads and temperature sensor, which is ready to be controlled with the Delta-T via PlaneWave Interface 3 software.
  • Three cooling fans blow out of the optical tube pulling air through the telescope and by the primary mirror. This helps the telescope to reach thermal equilibrium quickly. The fans are controlled by a switch on the optical tube, or can be controlled by via PWI3 software.


Optical system

Aperture 20" (508 mm)
Focal length
3454 mm
Focal ratio
Central obstruction
39% of primary mirror diameter
Backfocus from mounting surface
224 mm
OTA length
1194 mm
Optimal field of view 52 mm image circle
Carbon fibre truss and light shroud
Weight 63.5 kg

Primary mirror

Optical diameter
508 mm
Outer diameter 521 mm
Fused silica (quartz)
Prolate ellipsoid
Enhanced aluminium - 96%


Secondary mirror

191 mm
Fused silica (quartz)
Enhanced aluminium - 96%


Lens group

90 mm
Number of lenses
Broadband AR coatings (less than .5% reflected from 400 to 700nm)



  • CDK20 OTA
  • OTA cover to protect primary mirror
  • PlaneWave thumb drive with software and collimation instructions
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