12.5 inch CDK Optical Tube Assembly

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    12.5 inch CDK Optical Tube Assembly
    12.5 inch CDK Optical Tube Assembly

12.5 inch CDK Optical Tube Assembly

125101
Enquiry Item
The PlaneWave Instruments CDK12.5 is a 12.5 inch (0.32 m) f/8 Corrected Dall-Kirkham Astrograph telescope.

Enquire for more information or email us specifics at sales@astro.com.sg.

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12.5 inch CDK Optical Tube Assembly



Part   125101

The PlaneWave Instruments CDK12.5 is a 12.5 inch (0.32 m) f/8 Corrected Dall-Kirkham Astrograph telescope. The telescope has a closed carbon fiber tube, with 3 cooling fans ejecting air from the back of the telescope. The CDK12.5 covers a 52 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 46 lbs and comes standard with the large capacity 2.75 inch Hedrick focuser.

 

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.
The CDK Optical Design


FEATURES AND SPECIFICATIONS

SYSTEM
Aperture 12.5 inch   (318 mm)
Focal Length 2541 mm   (100.04 inch)
Focal Ratio f/8
Central Obstruction 42% of the Primary Mirror Diameter
Back Focus from Mounting Surface 10.445 inch   (265 mm)
Back Focus from Racked in Focuser 7.2 inch   (183 mm)
Weight (includes manual-focuser and dovetail) 46 lbs   (20.9 kg)
Weight (includes electronic-focuser and dovetail) 48.5 lbs   (22.0 kg)
OTA Length 31 inch   (787 mm)
Optical Tube Carbon Fiber
Optical Performance Vignetting and Spot Size Plots
Spot and Diffraction Diagrams
Overall Dimensions Overall Dimensions (PDF)

PRIMARY MIRROR
Diameter 13 inch   (330 mm)
Aperture 12.5 inch   (318 mm)
Focal Ratio f/3
Mounting Laser Collimated and Permanently Fixed
Material Precision Annealed Pyrex
Shape Prolate Ellipsoid
Coating Enhanced Aluminum - 96%

SECONDARY MIRROR
Diameter 4.65 inch   (118 mm)
Material Precision Annealed Pyrex
Shape Spherical
Coating Enhanced Aluminum - 96%

LENS GROUP
Diameter 70 mm   (2.76 inch)
Number of lenses 2
Coating Broadband AR Coatings (less than .5% reflected from 400 to 700nm)

STANDARD FEATURES
Carbon Fiber Tube 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
2.75 inch Hedrick Focuser Heavy duty no-slip focuser. The focus tube runs on 5 bearings and is driven by a leadscrew so there is no chance of slipping. It accepts an optional dial indicator and PlaneWave’s EFA Kit to control many electronic accessories. The draw tube travel is 1.3 inch.
Image 1
Image 2
Cooling Fans Three fans blow out of the optical tube pulling air though the telescope and by the primary mirror. This helps the telescope to reach thermal equilibrium quickly. The fans are controlled by a switch on the optical tube or can be conrolled by a computer if the optional Electronic Focus Accessory (EFA Kit) is purchased.

SHIPPING
Crated Shipping Weight 163 lbs   (73.9 kg)
Crate Width 23 inch   (584 mm)
Crate Height 31 inch   (787 mm)
Crate Length 41 inch   (1,041 mm)

INCLUDED ACCESSORIES
2.75\" to 2\" Adapter (125355) Adap ts the 2.75\" inner diameter of the focuser to a standard 2\" inner diameter. This adapter is necessary when setting the primary to secondary spacing. The 125399 Visual 2.75\" to 2\" adapter is an optional accessory that is designed to space a 2\" diagonal for visual use.
Ronchi Spacer (200354) This spacer 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.
OTA Cover The OTA cover is for closing the front of the tube to protect the primary mirror and the inside of the optical tube.
Printed Instructions For Collimation and Spacing
12VDC Power Supply (18778) Provides power for the fans (Not included for European Orders)
Wrench Set (5812A35) English Hex Wrenches (European Orders Only)


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