PlaneWave CDK20 Astrograph f/6.8 with Fused Silica Optics (1323220Q)

PlaneWave CDK20 Astrograph f/6.8 with Fused Silica Optics

Description:
The PlaneWave CDK20 is a 508 mm astrograph designed for demanding astronomical imaging with large-format CCDs. Its Corrected Dall-Kirkham (CDK) design provides a 52 mm flat field free from coma, astigmatism, and field curvature—delivering pinpoint stars edge to edge.

Fused Silica optics are used for maximum thermal and structural stability. This ultra-pure synthetic glass offers low expansion, high homogeneity, and resistance to thermal shock—ensuring constant focus and performance during long exposures and varying conditions. It is the material of choice for observatories worldwide.

Mechanically, the CDK20 uses a lightweight, rigid carbon fiber truss structure with an integrated aluminum dovetail and expansion joint to prevent stress between materials. 3D-printed internal baffles ensure perfect stray light suppression for enhanced contrast.

Spot diagrams confirm exceptional resolution across a 52 mm image circle at 430 nm, 585 nm, and 720 nm. At 21 mm off-axis, RMS spot sizes are just 6 microns, and at 26 mm (edge), only 11 microns—smaller than modern CCD pixels.

It is Delta-T Ready with integrated heaters and temperature sensors (controller #1329110 required). Six fans (rear and side) help the system reach thermal equilibrium quickly. The fans can be controlled manually or via PWI3 software if the EFA Kit is installed.

Technical specifications:

Optical design: Corrected Dall-Kirkham (CDK)
Aperture: 20" (508 mm)
Focal length: 3454 mm
F-ratio: f/6.8
Corrected field: 52 mm
Back focus: approx. 10.33"
Glass type: Fused Silica
Structure: Carbon fiber truss, 3D-printed baffles
Cooling system: 3 rear fans + 3 side fans
Delta-T Ready: yes (requires controller #1329110)
Mounting: 8" dovetail included
OTA weight: 288 lbs (132 kg)
OTA length: 62" (1651 mm)

Included accessories:

• 8" dovetail

• Dew heaters built-in (controller sold separately)

• OTA cover

• Soft secondary mirror cover

• USB drive with collimation software

• Allen wrench set (EU orders)

• 12V AC power adapter

Shipping crate required: reference #1323520 (charged separately)

Estimated shipping dimensions:
Width: 33" (838 mm)
Height: 33" (838 mm)
Length: 62" (1651 mm)
Gross weight: 288 lbs (132 kg)