PlaneWave CDK20 Telescope (f/7.77)
Starting Price: $39,000.00
Price as Configured: $39,000.00
Price as Configured: $39,000.00
Brand: PlaneWave Instruments / SKU: PW-200127Q
The CDK20 f/7.77 from PlaneWave Instruments stands as a pinnacle of engineering excellence, tailored for serious astrophotographers and astronomers who demand precision and performance. With its advanced technology and high-quality design, the CDK20 f/7.77 delivers outstanding images for a wide range of advanced observational and scientific applications.
The CDK20 f/7.77 is characterized by its exceptional specifications and features:
- 20-inch (508 mm) aperture
- 3951 mm focal length
- f/7.77 focal ratio
- 269.49 mm back focus from mounting surface
- Perfectly flat field across the entire 52mm image circle
- No off-axis coma or astigmatism
- Rock-solid fused silica mirrors with low thermal expansion
- Lightweight and rigid carbon fiber optical tube assembly
NOTE: Shipping cost will be determined after the order is made and must be paid for before the mount will ship. A shipping quote can be obtained on request.

Need help deciding?
Tell us what you're looking for, and we’ll point you in the right direction. Email Us.
Tell us what you're looking for, and we’ll point you in the right direction. Email Us.
Optical System
Aperture | 20 inch (508 mm) |
Focal Length | 3951 mm (155.55 inch) |
Focal ratio | f/7.77 |
Central Obstruction | 39% of the Primary Mirror Diameter |
Back Focus from mounting surface | 10.7 inch (271.98 mm) |
Weight | 140 lbs (63.5 kg) |
OTA Length | 47 inch (1,194 mm) |
Upper Cage | Carbon fiber truss |
Lower Cage | Carbon fiber truss with carbon fiber light shroud |
Optimal Field of View | 52mm image circle |
Secondary Mirror
Diameter | 7.5 inch (191mm) |
Material | Fused silica (quartz) |
Shape | Spherical |
Coating | Enhanced Aluminum – 96% |
Primary Mirror
Optical Diameter | 20 inch (508 mm) |
Outer Diameter | 20.5 inch (521 mm) |
Shape | Prolate ellipsoid |
Material | Fused silica (quartz) |
Coating | Enhanced aluminum – 96% |
Lens Group
Diameter | 90 mm (3.54 inch) |
Number of lenses | 2 |
Coating | Broadband AR Coatings (less than .5% reflected from 400 to 700nm) |
Optical Diameter | 20 inch (508 mm) |
Standard Features
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. |
Shipping
Crated Shipping Weight | 291 lbs (132.0 kg) |
Crate Width | 33 inch (838 mm) |
Crate Height | 33 inch (838 mm) |
Crate Length | 65 inch (1,651 mm) |
Included Accessories
Primary Mirror Cover | To protect the primary mirror |
PlaneWave Thumb Drive | Contains software and instructions for collimation and spacing the primary to secondary mirror |
12VDC Power Supply | Provides power for the fans |
|