PlaneWave CDK17 f/6.8 Optical Tube Assembly The CDK17 is a 432 mm Corrected Dall-Kirkham astrograph with a 2939 mm focal length and a flat, coma- and astigmatism-free 70 mm image circle, built for research and advanced deep-sky imaging.
Manufacturer model: PlaneWave CDK17 f/6.8 OTA (170101Q) · Specifications checked against manufacturer data on 2026-11-03
The CDK17 is a 432 mm Corrected Dall-Kirkham astrograph with a 2939 mm focal length and a flat, coma- and astigmatism-free 70 mm image circle, built for research and advanced deep-sky imaging.
Construction
Fused silica mirrors and a carbon fibre truss minimise focus shift with temperature. Cooling fans and a Delta-T-ready dew system keep the optics stable and clear.
Optical system
Optical design
Corrected Dall-Kirkham
Aperture
432 mm (17")
Focal length
2939 mm
Focal ratio
f/6.8
Central obstruction
23.7% by area; 48.6% of primary diameter
Image circle
70 mm
Optical performance
6.5 µm RMS at 21 mm; 9.6 µm at 26 mm off-axis
Primary mirror
432 mm optical / 445 mm outer, prolate ellipsoid, fused silica, enhanced aluminium 96%
Secondary mirror
190 mm spherical, fused silica, enhanced aluminium 96%
Corrector lenses
105 mm, broadband AR (<0.5% reflection, 400–700 nm)
Mechanical
Back focus from mounting surface
262.33 mm (10.32")
Back focus from racked-in focuser
184 mm (7.24")
OTA length
1067 mm (42")
Weight
48 kg (106 lb)
Upper / lower cage
Carbon fibre truss / carbon fibre truss with light shroud
PlaneWave CDK17 f/6.8 Optical Tube Assembly The CDK17 is a 432 mm Corrected Dall-Kirkham astrograph with a 2939 mm focal length and a flat, coma- and astigmatism-free 70 mm image circle, built for research and advanced deep-sky imaging.
Manufacturer model: PlaneWave CDK17 f/6.8 OTA (170101Q) · Specifications checked against manufacturer data on 2026-11-03
