Dall-Kirkham Optical Tube Assembly 12.5″

Part#: 125120

Price: $10,990.00

This is a Dall-Kirkham optical design with coatings that are optimized to transmit in infrared or ultra violet wavelengths.  It is diffraction limited across a 20mm image circle at the focal plane.  There are no refractive lens, only reflective components to the design.  For IR application, reflectives coatings are a protected gold which give better than 98% reflectivity from .65 micron (650nm) to 5 micron (5000nm).  This design is ideal for infrared astronomy or LIDAR applications.  UV optimized coatings can also be used at an additional cost.

The DK is available in the three different apertures, 24", 20", 17" and 12.5"


Aperture 12.5"
Focal Length 2541 mm
Central Obstruction 39%
Back Focus 10.445" from focuser mounting surface, 7.2" from racked in focuser
Weight 46 lbs
OTA Length 31"
Optical Tube Carbon Fiber
Optical Performance  Spot and Diffraction Diagrams
Dimensions Overall Dimensions


Diameter 4.65"
Material Precision Annealed Pyrex
Shape Spherical
Coating Protected Gold Reflective Coating - 98% (.65-16micron)

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. Focus may be automated through a computer using PlaneWave's EFA Kit add-on.. The draw tube travel is 1.3 inch.Image 1Image 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.
Crated Shipping Weight 163 lbs   (73.9 kg)
Crate Width 22 inch   (559 mm)
Crate Height 29 inch   (737 mm)
Crate Length 48 inch   (1,219 mm)