PlaneWave CDK20 Astrograph f/6.8

The CDK20 is an innovative telescope for unsurpassed astroimaging, research, or satellite tracking.

• f/6.8 and 3454 mm focal length.
• No coma, no off-axis astigmatism, and no field curvature.
• Pinpoint stars across a 52 mm 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.

Capturing the most stunning astrophotographs possible is something our team is passionate about. From design to manufacture, our goal with the Corrected Dall-Kirkham (CDK) 20″ telescope was centered around performance and ease of use. 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!

Carbon Fiber Truss Design

Minimizes thermal expansion which causes focus shift as temperature changes during an imaging session. Carbon fiber also reaches ambient temperatures quickly and is extremely lightweight and rigid to help ensure excellent imaging data is produced.

 

3D Printed Baffles

PlaneWave uses digital 3D printing technology to produce lightweight baffle tubes. 3D printers add successive layers of material to construct a baffle system with precision positioned internal stray light baffles to minimize vignetting and maximize image contrast. Quality baffling makes an incredible difference in overall image quality, so we ensured an optimal design was created for our telescopes.

 

Dovetail Expansion Joint

Allows for the difference in thermal expansion between carbon fiber and aluminum. The expansion joint allows the aluminum dovetail to expand and contract without stressing the carbon fiber lower truss. This results in images that are not distorted due to expansion, or contraction of the optical tube materials.

 

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.

 

 

Cooling Fans

Three fans on the backplate of the optical tube pull air through the telescope and by the primary mirror. Three fans on the side of the optical tube also blow air across the primary to ensure a boundary layer of air does not distort images. These fans help the telescope reach thermal equilibrium quickly, further reducing any distortion in images due to temperature variations. The fans are controlled by a switch on the optical tube, or can be controlled by via PWI3 software if a PlaneWave Electronic Focus Accessory (EFA Kit) is purchased.

Technical Specifications

Optical System

Secondary Mirror

Primary Mirror

Lens Group

Standard Features

Shipping

Included Accessories

In The Box

Manuals & Warranty

Planewave Warranty (one year for optical coatings and two years mechanics and electronics from the date of delivery)

Downloads

Articles

• Astronomy Technology Today: The PlaneWave Instruments CDK

Drawings & Diagrams

• CDK20 Optical Tube
• CDK20 Vignetting and Spot Size Plots
• CDK20 Piggyback Dovetail Plate Diagram

Camera Adapters Diagrams

• CDK20 IRF90 to Apogee Adapters
• CDK20 IRF90 to SBIG STX Adapters
• CDK20 to Apogee Adapters
• CDK20 to FLI Adapters
• CDK20 to SBIG Adapters

Software

• Delta-T Firmware Update (firmware 1.0.13219 and 2.1.16054)

Instructions

• Collimation and Spacing Instructions for CDK12.5, 14, 17, 20, and 24
• Cleaning Optics CDK14/17/20/24

Helpful Tools

• Pier Height Calculator