0.7m CDK Telescope System

Part#: 700101

Price: $200,000.00

PlaneWave Instruments now brings a fully automated observatory class telescope to the market in the CDK700, a 0.7 meter, Alt-Az telescope system. We are combining the revolutionary optical system that founded PlaneWave Instruments with a brand new innovative alt/az mount technology that sets a new standard for small observatory telescopes.

PlaneWave Instruments brings a fully automated observatory class telescope to the market with the CDK700, a 0.7 meter Alt-Az telescope system. We are combining the revolutionary CDK optical design that founded PlaneWave Instruments with an innovative direct-drive alt/az mount technology that sets a new standard for small observatory telescopes.

CDK700 Features

  • Pinpoint stars out to a 70mm image circle
  • 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 modeling 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 CDK700 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.  
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.  

 

 CDK Optical Design:

The CDK (Corrected Dall-Kirkham) Optical Design is an innovative solution for unsurpassed astroimaging quality at an affordable price. The CDK telescope design provides excellent imaging with large format CCD cameras while remaining superb for visual use. The CDK design far exceeds the off-axis performance of most commercial telescope designs including the Ritchey-Chrétien design.

Our design produces a flat, coma free and astigmatic free field of view. Since the secondary mirror is spherical, centering is very forgiving. This means it is easy to get the telescope optics aligned for optimum performance, which is not the case for most high-end astrographs. The end result at the image plane of the CDK design is no off-axis coma, no off-axis astigmatism, and a perfectly flat field all the way out to the edge of a 70mm image circle.  All this means that the stars will be pinpoints from the center of the field of view out to the corner of the field of view.

More about our Optical Design

 

 

OPTICAL SYSTEM

Optical Design Corrected Dall-Kirkham (CDK)
Aperture 700 mm (27.56 inch)
Focal Length 4540 mm
Focal ratio 6.5
Central Obstruction 47% of the Primary Mirror Diameter
Back Focus 305 mm (12 inch) from Mounting Surface
Weight 1,200 lbs
Optical Tube Dual truss structure with Nasmyth focus
Optical Performance 1.8 micron RMS spots [25mm on-axis] (400 to 900nm) 4.4 micron RMS spots [21mm off-axis] (400 to 900nm) 6.8 micron RMS spots [35mm off-axis] (400 to 900nm) Spot Diagram  
Dimensions 93.73" H x 43.25" W x 39" D    
Optimal Field of View 70 mm (0.86 degrees)
Focus Position Nasmyth Focus
Fully Baffled Field 60 mm
Image Scale 22 microns per arcsecond

MECHANICAL STRUCTURE

Fork Assembly Single piece U shaped fork arm assembly for maximum stiffness
Azimuth Bearing 20 inch diameter thrust bearing
Altitude Bearing 2 x 8.5 inch OD ball bearings
Optical Tube Dual truss structure with Nasmyth focus

MOTION CONTROL

Motor Control Industrial grade Parker brushless motor control system and built in electronics
Azimuth Motor Direct Drive 3 Phase Axial-Flux Torque Motor
Altitude Motor Direct Drive 3 Phase Axial-Flux Torque Motor
Encoder - Azimuth and Altitude 10 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 Torque Approximately 35 ft-lbs
Drive Electronics Capable 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 Software Incorporates PointXP mount modeling software by Dave Rowe All ASCOM compatible.

SYSTEM PERFORMANCE

Pointing Accuracy 10 arcsecond RMS with PointXP Model
Pointing Precision 2 arcsecond
Tracking Accuracy 1 arcsecond error over 3 minute period
System Natural Frequency 10 Hz or greater
Field De-Rotator Accuracy 3 microns of peak to peak error at 35mm off-axis over 1 hour of tracking (18 arc sec)

PRIMARY MIRROR BLANK SPEC

Radius of Curvature 4115mm
Optical Diameter 700 mm (27.56 inch)
Outer Diameter 714.38 mm (28.125 inch)
Core Diameter 203mm (8 inch)
Material Pyrex or Borosilicate Precision Annealed
Edge Thickness 2.25 inch
Cell 18 point

SECONDARY MIRROR BLANK SPEC

Radius of curvature 2961 mm
Thickness 25 mm
Optical Diameter 270 mm
Outer Diameter 280 mm
Cell 3 point RTV

TERTIARY MIRROR BLANK SPEC

Optical Major Diameter 152.4 mm
Thickness 25 mm


NOTE: All specifications and dimensions are subject to change. 
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