PlaneWave CDK20 F/7.7 OTA

PlaneWave CDK20 f/7.77 – 20-Inch Corrected Dall-Kirkham Telescope System

The CDK20 f/7.77 from PlaneWave Instruments stands as a pinnacle of optical precision, engineered for advanced astrophotographers, observatories, and research institutions seeking exceptional image quality and scientific performance. Utilizing PlaneWave’s signature Corrected Dall-Kirkham (CDK) optical system, the CDK20 f/7.77 eliminates common optical aberrations such as off-axis coma, field curvature, and astigmatism—producing an ultra-flat field across a generous image circle.

Housed in a lightweight yet structurally rigid carbon fiber optical tube, the CDK20 f/7.77 ensures long-term mechanical and thermal stability, even in challenging environmental conditions. With fused silica optics and generous back focus, this system is optimized for demanding visual and imaging configurations alike.

Key Specifications

Optical Design: Corrected Dall-Kirkham (CDK)
Clear Aperture: 508mm (20 in)
Focal Ratio: f/7.77
Focal Length: 3951mm
Back Focus: 269.49mm from mounting surface
Image Circle: 52mm
Mirror Material: Fused silica – low thermal expansion
OTA Material: Carbon fiber – lightweight and rigid

Performance & Applications

- Precision Imaging:
The CDK optical system delivers a perfectly flat, coma-free, and astigmatism-free image field, ideal for capturing sharp, detailed images across large-format CCD and CMOS sensors.

- Thermal Stability for Long Exposures:
Fused silica optics ensure minimal expansion under temperature changes, reducing focus drift and maintaining sharp star profiles throughout extended imaging sessions.

- Wide Instrument Compatibility:
With 269.49mm of back focus and a 52mm image circle, the CDK20 f/7.77 easily supports filter wheels, large-format cameras, adaptive optics systems, and spectrographs.

- Research & Educational Use:
Trusted by universities, remote observatories, and research facilities, the CDK20 is ideal for scientific photometry, deep-sky surveys, and precise data acquisition tasks.