17 inch CDK Optical Tube Assembly

Part#: 170101

Price: $22,000.00

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.
More about our Optical Design

 

Features:

Carbon Fiber Truss Design Open truss tube design with carbon fiber frame minimizes thermal expansion which causes focus shift with changes in temperature. Carbon fiber truss design also promotes quick thermal cooling and provides a rigid, lightweight structure.  
3D Printed Baffles Planewave uses digital 3D printing technology to produce lightweight baffle tubes. 3D printers add successive layers of material to construct a baffle system with precision positioned internal stray light baffles to minimize vignetting and maximize image contrast.  
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.  

 

CDK17 and Paramount MEII System Package:   $40,174

CDK 17 170101 $22,000
3.5” Hedrick Focuser 200340 $1,000
EFA Electronic Focus Accessory 240901 $1,000
Paramount MEII 600103 $15,000
Paramount MEII Versa Plate Accessory 600151 $299
Extension bar 600132 $175
Two extra 30# Counter Weights 600129 $700
TOTAL $40,174

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

PRIMARY MIRROR

Diameter 17.5 inch (445 mm)
Aperture 17 inch (432 mm)
Focal ratio f/3.24
Mounting Laser Collimated and Permanently Fixed
Material Precision Annealed Pyrex
Shape Prolate Ellipsoid
Coating Enhanced Aluminum - 96%

SECONDARY MIRROR

Diameter 190 mm (7.48 inch)
Material Precision Annealed Pyrex
Shape Spherical
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)
LoadingUpdating...