Plane Wave Delta Rho 500 f/3 telescope with Cassegrain focus (1323150)

Delta Rho 500 f/3 telescope with Cassegrain focus

Description:
The PlaneWave DeltaRho 500 is an ultra-fast, wide-field f/3 astrograph designed to revolutionize large-format astrophotography. With a 508 mm aperture and 1537 mm focal length, it delivers a 70 mm flat image circle and a 2.6° field of view—twice as large as the CDK20—while maintaining pinpoint stars across the entire frame.

The DeltaRho 500 uses a corrected Cassegrain focus design with the imaging train located behind the telescope, avoiding the mechanical and optical complications of prime focus systems. The fixed primary mirror ensures mechanical simplicity and thermal stability, while collimation is achieved easily via three secondary mirror tip/tilt screws.

The primary and secondary mirrors are both made of Fused Silica, known for its extreme thermal stability and optical precision. The secondary is spherical; the primary is a prolate ellipsoid. Advanced 3D-printed internal baffles reduce stray light and enhance contrast.

A three-element lens group with a 160 mm front lens and broadband AR coatings ensures <0.5% reflection between 400–700 nm. The integrated dew heaters on both mirrors are Delta-T Ready and can be controlled via PWI3 software (requires #1329200 controller, sold separately). Rear and side cooling fans bring the optics to ambient temperature quickly.

Constructed from carbon fiber, the OTA is stable, lightweight, and thermally inert. It’s compatible only with PlaneWave Serie-5 accessories, including the Serie-5XL focuser and rotator, which leave 147.6 mm of backfocus.

3D Printed Baffles 

PlaneWave’s digital 3D printing technology adds successive layers of material to our baffle systems for lightweight, precision-positioned internal stray light control to minimize vignetting and maximize image contrast.  

Collimation software

Along with the included collimation mask, PlaneWave Collimation software allows for quick and easy collimation necessary to maximize the performance of a fast f-ratio optical system. 

Delta-T Ready 

For added dew prevention, the DR500 is internally wired with polyimide film heater pads and a temperature sensor, which is ready to be controlled with the Delta-T via PWI 3 software. 

Carbon fiber optical tube and truss poles:

Carbon fiber is extremely lightweight and helps prevent thermal expansion that can distort an imaging system. This adds up to an extremely stable optical tube for an unsurpassed imaging experience.

Cooling fans:

Three Cooling fans have been strategically placed on the backplate and side of the Delta Rho optical tube in order to quickly cool the mirrors to ambient temperatures. Mirrors that are equilibrated to the ambient temperature help the telescope produce the highest quality astroimages possible. The fans are controlled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.

Technical specifications:

Optical design: Corrected Cassegrain
Aperture: 508 mm (20")
Focal length: 1537 mm (60.5")
F-ratio: f/3
Corrected image field: 70 mm (>2.6° FoV)
Back focus (no focuser/rotator): 9.166" (232.8 mm) from mounting surface, 7.271" (184.7 mm) from lens cell
Back focus (with Serie-5XL focuser + rotator): 5.81" (147.6 mm)
Central obstruction: 59% by diameter
Optical length: 892 mm (35.1")
OTA weight: 165 lbs (75 kg)
Tube material: Carbon fiber
Mount compatibility: PlaneWave L-500 or L-600
Accessory compatibility: Serie-5 devices only
Delta-T Ready: yes (controller #1329200 required)
Cooling system: 3 fans (rear and side-mounted)

Primary mirror:

• Diameter: 508 mm

• Shape: Prolate ellipsoid

• Material: Fused Silica

• Coating: Enhanced aluminium (96%)

Secondary mirror:

• Diameter: 286 mm

• Shape: Spherical

• Material: Fused Silica

• Coating: Enhanced aluminium (96%)

Lens group:

• Largest lens: 160 mm

• Number of lenses: 3

• Coatings: Broadband AR (<0.5% reflectivity from 400–700 nm)

Included accessories:

• Built-in dew heaters with sensors (controller not included)

• OTA cover

• Soft secondary mirror cover

• Flash drive with software and collimation guide

• Allen wrench set (EU only)

Shipping dimensions: not specified (estimated OTA weight: 75 kg)