17" CDK Optical Tube Assembly
17" CDK Optical Tube Assembly
17" CDK Optical Tube Assembly
17" CDK Optical Tube Assembly
17" CDK Optical Tube Assembly

Planewave

17" CDK Optical Tube Assembly

Regular price
$ 19,500.00
Sale price
$ 19,500.00
Unit price
per 

This item is out of stock but you can place an order now and we’ll ship when it becomes available.

Description

The PlaneWave Instruments CDK17 is a 17 inch (0.43 m) f/6.8 Corrected Dall-Kirkham Astrograph telescope. The CDK17 has a dual carbon-fiber truss design, with 3 cooling fans ejecting air from the back of the telescope, and 4 fans blowing across the boundary layer of the mirror's surface. The CDK17 covers a 70 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 94 lbs (43 kg) and comes standard with a back plate retaining ring ready to accept the focuser of your choice.

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.

This no-compromise design is unique in making the optical alignment forgiving and collimation very easy. This guarantees the user the best possible performance from the telescope. The end result at the image plane of the CDK design is no off-axis coma, no off-axis astigmatism, perfectly flat field (no off-axis defocus). The CDK design will give you pinpoint stars from the center to the corner of the field of view.

Specification

OPTICAL SYSTEM

Optical Design Corrected Dall-Kirkham
Aperture 17 inch (432 mm)
Focal Length 2939 mm (115.71 inch)
Focal ratio F/6.8
Central Obstruction 23.7% by surface area; 48.6% of the Primary Mirror Diameter
Back Focus from Mounting Surface 10.24 inch (260 mm)
Back Focus from Racked in Focuser 7.24 inch (184 mm)
Weight 106 lbs (48 kg)
OTA Length 42 inch (1067 mm)
Optical Performance 6.5 micron rms at 21mm and 9.6 micron at 26mm off-axis
Upper Cage Carbon Fiber Truss
Lower Cage Carbon Fiber Truss with Carbon Fiber Light Shroud
Optimal Field of View 70mm Image Circle

 

SECONDARY MIRROR

Diameter 190 mm (7.48 inch)
Material Precision Annealed Pyrex
Shape Spherical
Coating Enhanced Aluminum - 96%

 

 

 

 

PRIMARY MIRROR

Optical Diameter 17 inch (432 mm)
Outer Diameter 17.5 inch (445 mm)
Shape Prolate Ellipsoid
Material Precision Annealed Borosilicate or Fused Silica
Coating Enhanced Aluminum - 96%

 

 

 

LENS GROUP

Diameter 105 mm (4.13 inch)
Number of lenses 2
Coating Broadband AR Coatings (less than .5% reflected from 400 to 700nm)

 


STANDARD FEATURES

Carbon Fiber Truss Design Minimizes thermal expansion which causes focus shift with changes in temperature
Dovetail Expansion Joint Allows for the difference in thermal expansion between carbon fiber and aluminum. The expansion joint allows the aluminum dovetail expand and contract without stressing the carbon fiber lower truss
Cooling Fans Three cooling fans ejecting air from the back of the telescope and four fans blowing across the boundary layer of the mirror surface. This helps the telescope to reach thermal equilibrium quickly. The fans are controlled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.

SHIPPING

Crated Shipping Weight 225 lbs   (102.1 kg)
Crate Width 30 inch   (762 mm)
Crate Height 37 inch   (940 mm)
Crate Length 58 inch   (1,473 mm)

INCLUDED ACCESSORIES

Ronchi Spacer (600341 & 600343) This spacer sits in place of a focuser and is used for setting the primary to secondary spacing. It has an 1-1/4 inner diameter and may be used with 1-1/4 oculars for collimation
Ronchi Ocular This ocular is a Ronchi screen used for setting the primary to secondary spacing
Primary Mirror Cover The Primary Mirror Cover protects the primary mirror
Planewave Thumb Drive Containing all documentation and software for collimation and spacing
12VDC Power Supply Provides power for the fans (Not included for European Orders)
Wrench Set (5812A35) English Hex Wrenches (European Orders Only)

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