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RC700 Ritchey-Chrétien Observatory System

SKU# 700126Q

Price: $210,000.00


PlaneWave Instruments brings a fully automated observatory class telescope to the market with the PW700-RC, a 0.7 meter Alt/Az telescope system with Ritchey-Chrétien (RC) optics. We have combined Ritchey-Chrétien optics with PlaneWave’s direct-drive alt/az mount technology to set a new standard for research-class observatory telescopes. The RC700 is a favorite among free-space optical communication clients.


PlaneWave Instruments brings a fully automated observatory class telescope to the market with the PW700-RC, a 0.7 meter Alt/Az telescope system with Ritchey-Chrétien (RC) optics. We have combined Ritchey-Chrétien optics with PlaneWave’s direct-drive alt/az mount technology to set a new standard for research-class observatory telescopes.

Optical Design

PlaneWave’s CDK astrographs have become the telescopes of choice for universities, industry, and astrophotographers around the world. Now PlaneWave offers the PW-RC series to meet the custom needs of the scientific community.

The PW700-RC in its native format (no field flattening lenses) uses only mirror with reflective coatings. This can be useful when making observations primarily on-axis and wide field imaging is not a concern.

RC700 Features

  • Ritchey-Chrétien optical design
  • Dual Nasmyth focus, allowing simultaneous mounting of two instruments or easy switching between visual and imaging use
  • Direct-drive motors on each axis for smooth, fast, and virtually silent movement of the telescope
  • High-resolution encoders on each axis for precise positioning
  • Zero backlash
  • Zero periodic error
  • PointXP mount modelling software
  • Field de-rotator / rotational field framing

An alt/az mount is inherently more stable than an equatorial mount since there is no cantilevered mass, nor are there any large protruding counterweights to create a dangerous hazard in a public observatory. An alt/az telescope is also considerably more compact than its equatorial counterpart, allowing a larger telescope to fit in a smaller enclosure. The mass it takes to make a rigid alt/az mount is substantially less, leading to cost savings. Unlike German Equatorial mounts, there are no meridian flips to deal with. You can image from horizon to horizon continuously if desired. Alt/Az is more intuitive to use and no polar alignment is needed. Besides, it is the way the big boys do it!

Benefits of Nasmyth Focus

The Nasmyth Focus is along the altitude axis so there are virtually no balancing issue as you change out equipment. Eyepieces remain at a constant wheelchair-accessible height, greatly simplifying access to the telescope for public observatories. The rotating tertiary mirror allows you to switch from one Nasmyth port to the other in just seconds, allowing observers to easily transition between imaging and visual use.


Rotating Tertiary Mirror

The PW700-RC includes an integrated rotator for the tertiary mirror, with magnetic locks to position the mirror precisely for either Nasmyth focus position. The rotator can move from one port to the other in under 10 seconds. Tertiary Mirror Video


Direct drive motors and encoders

Direct Drive motors mean that there are no gears to cause backlash and periodic error. With high-resolution encoders providing the feedback for the direct drive motors, not only will the telescope track without periodic error or have any backlash at all, but the mount will be able to counter against wind gusts. The direct drive motors can move the telescope at incredible speeds for tracking satellites or just to minimize target acquisition time.




Optical System

Optical DesignRitchey-Chrétien
Aperture700 mm (27.56 inch)
Focal Length4540 mm
Focal ratio6.5
Central Obstruction47% of the Primary Mirror Diameter
Back Focus309 mm (12.2 inch) from Mounting Surface
Weight1,200 lbs
Optical TubeDual truss structure with Nasmyth focus
Dimensions93.73″ H x 43.25″ W x 39″ D
Focus PositionNasmyth Focus

Mechanical Structure

Fork AssemblySingle piece U shaped fork arm assembly for maximum stiffness
Azimuth Bearing20 inch diameter thrust bearing
Altitude Bearing2 x 8.5 inch OD ball bearings
Optical TubeDual truss structure with Nasmyth focus

Motion Control

Motor ControlIndustrial grade Parker brushless motor control system and built in electronics
Azimuth MotorDirect Drive 3 Phase Axial-Flux Torque Motor
Altitude MotorDirect Drive 3 Phase Axial-Flux Torque Motor
Encoder – Azimuth and Altitude10 inch disk built into the azimuth and altitude axes with stainless steel encoder tape on the circumference with reader yields 16 million counts per revolution of the telescope. This translates to about 0.08 arcsecond resolution.
Motor TorqueApproximately 35 ft-lbs
Drive ElectronicsCapable of controlling up to 4 high speed encoders, limit switch inputs, homing switch inputs, controls two additional motors for accessories, two brake outputs and 16 digital and 2 analog inputs
Telescope Control SoftwareIncorporates PointXP mount modeling software by Dave Rowe All ASCOM compatible.

System Performance

Pointing Accuracy10 arcsecond RMS with PointXP Model
Pointing Precision

2 arcseconds at sidereal velocity

Tracking Accuracy

< 1 arcsecond over a 10 minute period at sidereal velocity

System Natural Frequency10 Hz or greater
Field De-Rotator Accuracy3 microns of peak to peak error at 35mm off-axis over 1 hour of tracking (18 arc sec)

Primary Mirror

Radius of Curvature4115mm
Optical Diameter700 mm (27.56 inch)
Outer Diameter714.38 mm (28.125 inch)
Core Diameter203mm (8 inch)
MaterialFused Silica
Edge Thickness2.25 inch
Cell18 point

Secondary Mirror

Radius of curvature2961 mm
Thickness25 mm
Optical Diameter312.4mm (12.3 inch)
Outer Diameter317.5mm (12.5 inch)
MaterialFused Silica
Cell3 point RTV

Tertiary Mirror

Optical Major Diameter152.4 mm
Thickness25 mm
MaterialFused Silica

NOTE: All specifications and dimensions are subject to change.  

For warranty information please check our Standard Warranty Page

Included Items

Included Items

Heating elements for dew preventionThe heating pads on the primary and secondary mirror require the 600195 Delta-T controller sold separately
OTA CoverTo protect the primary mirror and inside of the optical tube
FlashdriveContains software and instructions for collimation and spacing the primary to secondary mirror
EFA Kit and IRF90Port one includes an IRF90 and EFA kit for focusing and derotating within PWI2 software and also relaying mirror temperature data back to the control computer.
Feathertouch Focuser and AdapterUsed for visual observing through Port 2 with a user supplied eyepiece.