Planewave CDK20 f/7.7 Optical Tube Assembly

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.

Key Features Overview

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
• About the CDK20 f/7.7 Optical Tube Assembly

  CDK20 f/7.77’s Key Features

  Large Aperture and Moderate Focal Ratio

  The CDK20 f/7.77 features a 508 mm aperture and a high f/7.77 focal ratio. This configuration provides excellent light-gathering efficiency and image scale, making it ideal for detailed lunar, planetary, and deep-sky imaging.

  Advanced Optical Design

  The CDK20 f/7.77 has a state-of-the-art Corrected Dall-Kirkham optical system that offers exceptional image clarity. This design eliminates off-axis coma and astigmatism and delivers a perfectly flat field, ensuring that images are crisp and detailed across the entire field of view with minimal post-processing required.

  Robust Mechanical Structure

  Constructed with a carbon fiber optical tube, the CDK20 f/7.77 is lightweight and sturdy. Its thermal expansion coefficient ensures minimal focus shift with temperature changes, making it suitable for extended observing sessions under diverse environmental conditions.

  High-Performance Mirrors and Coatings

  Featuring fused silica mirrors, the CDK20 f/7.77 maintains precise optical alignment and surface accuracy, even with temperature fluctuations. Its high-quality coatings maximize light transmission and minimize stray light, optimizing performance for critical observational tasks.

  Thermal Management

  The CDK20 f/7.77 includes cooling fans and a Delta-T ready system to achieve thermal equilibrium rapidly. These features reduce air turbulence within the tube, minimizing image distortion and maintaining consistent imaging quality.

  Integrated Dew Control

  The telescope incorporates advanced dew prevention technology with heater pads controlled by PlaneWave’s software. This ensures optical surfaces remain clear of condensation in humid conditions, maintaining clear and consistent imaging performance.

  Application-Specific Benefits

  Astrophotography

  With its precise focal ratio and large image circle, the CDK20 f/7.77 allows astrophotographers to capture detailed and expansive views of the cosmos, providing incredible detail and clarity.

  Astronomy Research

  The stable and precise imaging capabilities of the CDK20 f/7.77 make it an invaluable tool for academic institutions and observatories engaged in sophisticated astronomical research, including detailed photometric studies and complex deep-sky surveys.

  Visual Observations

  The CDK20 f/7.77 excels in visual observation, offering bright and crisp views ideal for star parties and serious visual astronomy. The telescope's significant aperture and excellent optical quality provide stunning views of planetary, lunar, and deep-sky objects, making every viewing session a memorable experience.

  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.

  Aperture508 mm (20")Focal Length3951 mm (156")Focal Ratiof/7.7Central Obstruction39% of the Primary Mirror DiameterBack Focus from Mounting Surface269.24 mm (10.6")Weight140 lbs (63.5 kg)OTA Length1194 mm (47")Optical Design Performance1.5-micron RMS on-axis, 3.8-micron RMS at 12 mm off-axis, 6.0-micron at 21 mm off-axisUpper CageCarbon fiber trussLower CageCarbon fiber truss and light shroudImage Circle Size52 mm

  Diameter	90 mm (3.54")
  Coating	Broadband AR Coatings (less than .5% reflected from 400 to 700 nm)
  Optical Diameter	508 mm (20")

  Diameter191 mm (7.5")MaterialFused silica (quartz)ShapeSphericalCoatingEnhanced Aluminum - 96%

  Optical Diameter508 mm (20")Outer Diameter521 mm (20.5")ShapeProlate EllipsoidMaterialFused Silica (quartz)CoatingEnhanced 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
  	OTA Cover - To protect the primary mirror and inside of the optical tube
  	Flashdrive - Contains software and instructions for collimation and spacing the primary to secondary mirror
  	Wrench Set (5812A35) - Standard hex wrenches (European orders only)