PlaneWave DeltaRho 500 f/3 Optical Tube Assembly The DeltaRho 500 is a fast 508 mm corrected-Cassegrain astrograph with a 1537 mm focal length (f/3.03) and a flat 70 mm image circle covering more than 2.6 degrees. It is designed for wide-field surveys, space domain awareness and demanding astrophotography.
Manufacturer model: PlaneWave DeltaRho 500 f/3.03 OTA · Specifications checked against manufacturer data on 2026-11-03
The DeltaRho 500 is a fast 508 mm corrected-Cassegrain astrograph with a 1537 mm focal length (f/3.03) and a flat 70 mm image circle covering more than 2.6 degrees. It is designed for wide-field surveys, space domain awareness and demanding astrophotography.
Construction
Carbon fibre truss poles and shroud keep the tube rigid and thermally stable. Collimation software supports quick alignment, and integrated heaters keep the optics clear of dew. Optional Series-5XL focuser and Series-5 de-rotator are controlled through PWI4.
Optical system
Optical design
Corrected Cassegrain focus
Aperture
508 mm (20")
Focal length
1537 mm
Focal ratio
f/3.03
Central obstruction
59% by diameter
Image circle
70 mm (>2.6°)
Optical performance
3.86 µm RMS on-axis; 4.04 µm at 22 mm; 6.04 µm at 35 mm off-axis
Primary mirror
508 mm optical / 528 mm outer, prolate ellipsoid, fused silica, enhanced aluminium 96%
Secondary mirror
286 mm spherical, fused silica, enhanced aluminium 96%
Corrector lenses
160 mm, broadband AR (avg. <0.5% reflection, 400–700 nm)
Mechanical
Back focus
232.8 mm from mounting surface; 184.7 mm from lens cell; 147.6 mm with Series-5XL focuser and rotator (extension spacer required)
PlaneWave DeltaRho 500 f/3 Optical Tube Assembly The DeltaRho 500 is a fast 508 mm corrected-Cassegrain astrograph with a 1537 mm focal length (f/3.03) and a flat 70 mm image circle covering more than 2.6 degrees. It is designed for wide-field surveys, space domain awareness and demanding astrophotography.
Manufacturer model: PlaneWave DeltaRho 500 f/3.03 OTA · Specifications checked against manufacturer data on 2026-11-03
