Planewave Europe

PlaneWave CDK20 Astrograph f/7.77

The 20" CDK is a telescope optical system that is designed to excel at imaging on large format CCD cameras while remaining an excellent instrument for visual use.

Capturing the most stunning astrophotographs possible is something our team is passionate about. From design to manufacture, our goal with the Corrected Dall-Kirkham (CDK) 20″ telescope was centered around performance and ease of use. The CDK20 is an incredible breakthrough in telescope technology and produces no off-axis coma and no off-axis astigmatism. Additionally, the CDK20 provides a perfectly flat field so your astrophotographs will have stunning clarity from corner to corner of the image without field curvature degrading the photos. Offering the simplicity of single-mirror collimation, the stray light control of advanced baffles, structural performance created through finite element analysis (FEA), and decades of telescope design experience, the CDK20 is an exceptional diffraction-limited telescope. CDK20 users can experience pinpoint stars edge-to-edge and a 45 x 45 arcminute field of view when using large 16803 size camera sensors. When equipment fades into the background and simply performs, the astrophotography experience becomes even more fun and rewarding!

The telescope is also available in Ritchey-Chrétien (RC) optics and infrared optimized.

CDK 20 Astrograph, 20 inch with Fused Silica Optics
Additional 1.9″ of backfocus and 497 mm of focal length compared to the standard CDK20 f/6.8 model.
modified to Dall-Kirkham, with fully corrected image field
with 8" Dovetail, focal length 3.951mm (f/7.77)
Pinpoint stars across a 52mm image circle.
Delta T Ready, 3,5" Hedrick Focuser and EFA Kit separately available
Requires a crating #1323520. The crating will be charged extra

Features

Carbon Fiber Truss Design:

Minimizes thermal expansion which causes focus shift as temperature changes during an imaging session. Carbon fiber also reaches ambient temperatures quickly and is extremely lightweight and rigid to help ensure excellent imaging data is produced.

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. Quality baffling makes an incredible difference in overall image quality, so we ensured an optimal design was created for our telescopes.

Dovetail Expansion Joint:

Allows for the difference in thermal expansion between carbon fiber and aluminum. The expansion joint allows the aluminum dovetail to expand and contract without stressing the carbon fiber lower truss. This results in images that are not distorted due to expansion, or contraction of the optical tube materials.

Delta-T Ready:

For added dew prevention, the CDK20 is internally wired with polyimide film heater pads and temperature sensor, which is ready to be controlled with the Delta-T via PlaneWave Interface 3 software.

Cooling Fans:

Three fans on the backplate of the optical tube pull air through the telescope and by the primary mirror. Three fans on the side of the optical tube also blow air across the primary to ensure a boundary layer of air does not distort images. These fans help the telescope reach thermal equilibrium quickly, further reducing any distortion in images due to temperature variations. The fans are controlled by a switch on the optical tube, or can be controlled by via PWI3 software if a PlaneWave Electronic Focus Accessory (EFA Kit) is purchased.

Fused Silica

Fused Silica 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.

Scope of delivery

Heating elements for dew prevention – The heating pads on the primary and secondary mirror require the #1329110 Delta-T controller and sold separately
OTA cover – To protect the primary mirror and inside of the optical tube
Flash Drive – Contains software and instructions for collimation and spacing the primary to the secondary mirror
Wrench Set(5812A35) – Standard hex wrenches (European orders only)
Soft cover for secondary mirror
12v AC adapter

Shipping: dimensions and weight

Width

33 inch (838 mm)

Height

33 inch (838 mm)

Length

62 inch (1,651 mm)

Weight

288 lbs (132.0 kg)

The information is only a rough estimate! The actual shipping dimensions and weight may differ.

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