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 PlaneWave Instruments CDK20 is a 20-inch (0.51 m) f/7.77 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.
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.
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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 |
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