CDK20 f/6.8 Optical Tube Assembly
$34,000.00
The CDK20 from PlaneWave Instruments is crafted with precision engineering and cutting-edge technology, making it ideal for dedicated astrophotographers and discerning astronomers. With its robust design and advanced features, the CDK20 is well-suited for various advanced observational and scientific applications, consistently delivering high-quality images.
*Price excludes shipping and crating. See our crating and pricing policy for full details.
Key Features Overview
The CDK20 f/6.8 stands out with its impressive specifications and features:
- 20-inch (508 mm) aperture
- 3454 mm focal length
- f/6.8 focal ratio
- 224 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
CDK20’s Key Features
Large Aperture and Moderate Focal Ratio
The CDK20 f/6.8 features a significant 508 mm aperture and an f/6.8 focal ratio. This combination provides excellent light-gathering capabilities and a wide field of view, enhancing its ability to capture detailed images of deep-sky objects for astrophotography and research purposes.
Advanced Optical Design
Equipped with a state-of-the-art Corrected Dall-Kirkham optical system, the CDK20 offers unmatched image clarity. It eliminates off-axis coma and astigmatism and provides a perfectly flat field, ensuring images are crisp and detailed across the entire field of view, requiring minimal post-processing.
Robust Mechanical Structure
Built with a carbon fiber optical tube, the CDK20 is both durable and lightweight. Its design minimizes thermal expansion, ensuring minimal focus shift with temperature changes, which is ideal for extended observing sessions under diverse environmental conditions.
High-Performance Mirrors and Coatings
Utilizing fused silica mirrors, the CDK20 maintains precise optical alignment and exceptional surface accuracy, even during temperature fluctuations. The high-quality coatings improve light transmission and reduce stray light, optimizing the telescope's performance for specialized observational tasks.
Thermal Management
The CDK20 has cooling fans and a Delta-T ready system to achieve thermal equilibrium swiftly. These features help reduce air turbulence within the tube, thus minimizing image distortion and maintaining consistent imaging quality.
Integrated Dew Control
The telescope includes advanced dew prevention technology with heater pads controlled by PlaneWave’s software. This ensures optical surfaces remain free from condensation in humid conditions, thus maintaining clear and consistent imaging performance.
Application-Specific Benefits
Astrophotography
With its large image circle and exceptional field flatness, the CDK20 allows astrophotographers to capture expansive and breathtaking views of the cosmos with incredible detail and clarity.
Astronomy Research
The stable and precise imaging capabilities of the CDK20 make it an invaluable asset for academic institutions and observatories engaged in sophisticated astronomical research, including deep-sky surveys and detailed photometric studies.
Visual Observations
The CDK20 excels in visual observation, providing bright and clear views ideal for star parties and serious visual astronomy. Its large aperture and superior optical quality deliver stunning views of planetary, lunar, and deep-sky objects, making every viewing session a memorable experience. Here's the updated article adapted for the CDK17 based on the features and specifications from the provided product page:
Space Situational Awareness (SSA) and Space Domain Awareness (SDA)
The CDK20 also lends itself to Space Situational Awareness and Space Domain Awareness applications. Its capability to provide detailed observations can be essential for tracking and monitoring satellites and other space debris, contributing valuable data for space traffic management and safety initiatives.
Specifications
CDK20 f/6.8 Optical Tube Assembly
| Aperture | 508 mm (20") |
| Focal Length | 3454 mm (136") |
| Focal Ratio | f/6.8 |
| Central Obstruction | 39% of the Primary Mirror Diameter |
| Back Focus from Mounting Surface | 224 mm (8.81") |
| Weight | 140 lbs (63.5 kg) |
| OTA Length | 1194 mm (47") |
| Optical Design Performance | 1.5-micron RMS on-axis, 3.8-micron RMS at 12 mm off-axis, 6.0-micron at 21 mm off-axis |
| Upper Cage | Carbon fiber truss |
| Lower Cage | Carbon fiber truss and light shroud |
| Image Circle Size | 52 mm |
| Diameter | 90 mm (3.54") |
| Coating | Broadband AR Coatings (less than .5% reflected from 400 to 700 nm) |
| Diameter | 191 mm (7.5") |
| Material | Fused silica (quartz) |
| Shape | Spherical |
| Coating | Enhanced Aluminum - 96% |
| Optical Diameter | 508 mm (20") |
| Outer Diameter | 521 mm (20.5") |
| Shape | Prolate Ellipsoid |
| Material | Fused Silica (quartz) |
| Coating | Enhanced Aluminum - 96% |
| Included Items | Heating Elements for Dew Prevention - The heating pads on the primary and secondary mirror require the 600195 Delta-T controller sold separately |
| Flashdrive - Contains software and instructions for collimation and spacing the primary to secondary mirror | |
| Wrench Set (5812A35) - Standard hex wrenches (European orders only) | |
Recommended Products
| Image | Name | Summary | Price | Buy |
|---|---|---|---|---|
 | Solid Aluminum Shrouds | Enhance the protection of your telescope’s primary mirror with our Solid Aluminum Shrouds. Specifically designed for OTAs like the CDK14, CDK17, CDK20, and CDK24, these ruggedized shrouds offer debris and light mitigation ensuring optimal optical performance.
*Factory installation required for all OTAs | $600.00 – $1,150.00 | |
 | L-500 Direct-Drive Telescope Mount | The PlaneWave L-500 Direct Drive Mount embodies the pinnacle of engineering precision, designed to meet the rigorous demands of advanced astrophotographers and astronomical researchers. As a critical part of our L-Series, this mount leverages sophisticated technology to provide an unmatched observational platform. *Price excludes shipping and crating. See our crating and pricing policy for full details. Key Features OverviewThe L-500 distinguishes itself with its significant specifications and features:
| $22,500.00 | |
 | L-550 Direct-Drive Telescope Mount | The PlaneWave L-550 Direct Drive Mount exemplifies advanced engineering, tailored to exceed the expectations of astrophotography enthusiasts and astronomy researchers. As a robust member of our L-Series, the L-550 integrates superior technology to deliver an exceptional observational platform. *Price excludes shipping and crating. See our crating and pricing policy for full details. Key Features OverviewIts impressive specifications and features that distinguish the L-550:
| $30,000.00 | |
 | Portable Rolling Pier | Don’t let bad weather stop you from enjoying your L-Series Mount every clear night. The Portable Rolling Pier lets you move your L-series Mount and telescope to the best spot for stargazing in no time. Just grab the steering T-handle and roll it wherever you want! With the auto-mount modeling feature in our PWI software, your L-Mount will be ready to capture amazing night sky images in minutes. | $8,700.00 | |
 | Electronic Focus Accessory (EFA) Kit |
*If the EFA is not purchased, the ability to automate temperature regulation for the primary mirror will be lost. This is especially significant when using a third-party focuser, as the EFA is required for full automation. | $920.00 – $1,150.00 | |
 | Fabric Light Shroud | This is a spandex fabric light shroud that blocks out stray light and minimizes dust on the primary mirror. Available for the CDK14, CDK17, CDK20, CDK24, and CDK700. | $140.00 – $790.00 | |
 | Delta T Heater |
| $750.00 | |
 | Telescope Dovetail Saddles | The Keller EZ Saddle (600182) accepts Losmandy D-style dovetail rails such as the CDK12.5, CDK14, and DeltaRho 350. This saddle comes standard with the L-350 mount and can also be attached to the outside arm of any L-series mount for dual-mounted OTA configurations. The PlaneWave Wide Saddle (200919) comes standard with L-500, L-550, and L-600 mounts for securing CDK17, CDK 20, CDK24, and DeltaRho 500 telescopes. | $400.00 | |
 | IRF90 – Integrated Rotating Focuser |
| $5,200.00 | |
 | Piggyback Dovetail Bars |
Please Note- For CDK17 users:
| $400.00 – $650.00 | |
 | Hedrick Focuser |
| $1,150.00 | |
 | L-500/L-600 Equatorial Wedge |
| $3,500.00 | |
 | Visual Adapter – CDK20/24 | This 3.5″-2″ Visual Adapter, for the CDK20 and CDK24, slides into the optional 3.5″ Hedrick Focuser.
| $160.00 | |
 | Finderscope and Mounting Bracket | The back plate on all of the CDK models has four mounting positions for a finder mounting plate.
| $460.00 | |
 | 2 inch Mirror Diagonal |
| $394.00 | |
 | Shroud and Mirror Cover Spacers |
| $312.00 – $1,712.00 | |
 | Mounting Bracket for Finderscopes |
| $50.00 | |
 | Reducer 0.66x CDK20 / CDK24 | This reducer is specifically crafted for telescopes with a flat image field, such as CDKs, reducing the aperture ratio to 66% for faster imaging and enhanced optical performance. | $1,400.00 |
