PlaneWave IRDK24 Dall-Kirkham f/6.5

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PlaneWave IRDK24 Dall-Kirkham f/6.5

# 1323224IQ

€ 77,400.00 Price excl. German VAT tax (19%): € 65,042.02

  • IRDK 24 Astrograph, 24 inch Infrared optimized with Fused Silica
  • a Dall-Kirkham optical design with coatings that are optimized to transmit in infrared or ultra violet wavelengths
  • 8" Dovetail, focal length 3.962 mm (f/6.5)
  • Delta T Ready, 3,5" Hedrick Focuser and EFA Kit separately available

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PlaneWave IRDK 24" DAll-Kirkham

Planewave Dall-Kirkham Optical Tube Assembly

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", 28" and 12,5".

Fused Silicia is a synthetic amorphous silica glass of the highest purity and one of the most transparent glasses made. The optical and thermal properties of fused silica are superior to other types of glass due to its purity. Its transmission and homogeneity exceed those of crystalline quartz without the problems of temperature instability inherent in the crystalline form. Fused Silica has a coefficient of thermal expansion six times lower than Borosilicate (Pyrex) glass, which means that as fused silica cools down, it preserves its shape to a high degree of accuracy. This translates into consistent optical performance and unchanging focus over temperature changes. With its high melting temperature ()~ 1.600 degree Celsius), a very low coefficient of thermal expansion and resistance to thermal shock, fused silica is the material of choice for professional observatories as well as various scientific applications.



Aperture 24 inch (610 mm)
Focal Length 3962 mm (155.98 inch)
Focal ratio f/6.5
Central Obstruction 47% of the Primary Mirror Diameter
Back Focus from Mounting Surface 14.1 inch (358 mm)
Back Focus from Racked in Focuser 5.81 inch (148 mm)
Weight 240 lbs (108.9 kg)
OTA Length 56 inch (1,422 mm)
UpperCage Carbon Fiber Truss
Lower Cage Carbon Fiber Truss with Aluminum Light Shroud
OTA Width 31 inch (787 mm)
OTA Height 35 inch (889 mm)
Optimal Field of View 70mm Image Circle


Diameter 9.45 inch (240 mm)
Material Fused Silica
Shape Spherical
Coating IR or UV optimized


Aperture 24 inch (610 mm)
Diameter 24.5 inch (622 mm)
Focal ratio f/3.2
Shape Prolate Ellipsoid
Material Fused Silica
Coating IR or UV optimized


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
Cooling Fans Three cooling fans blow air inside the back of the telescope. 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.
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Additional Information

Manufacturer Planewave
SKU (#) 1323224IQ
Manufacturer SKU (#) 240120Q
EAN Code 4047825035127
Optical Design Dall-Kirkham
Aperture (mm) 24" (610 mm)
Focal Length 3.962 mm (155.98 inch)
Focal Ratio f/6.5
Image Field 70 mm
Back Focus Distance 14.1" (358 mm) from Mounting Surface, 5.81" (148 mm) from Racked in Focuser
Central Obstruction 47% of the Primary Mirror Diameter
Substrate Fused Silica
Length of tube 1.422 mm
Optical length (mm) 55,98 inch (1.422 mm)
Optical Tube Weight 240 lbs (109 kg)
Mount No mount (OTA only)

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