CDK20’s Key Features

Large Aperture and Moderate Focal Ratio

The CDK20 f/6.8 features a significant 508 mm aperture and an f/6.8 focal ratio. This combination provides excellent light-gathering capabilities and a wide field of view, enhancing its ability to capture detailed images of deep-sky objects for astrophotography and research purposes.

Advanced Optical Design

Equipped with a state-of-the-art Corrected Dall-Kirkham optical system, the CDK20 offers unmatched image clarity. It eliminates off-axis coma and astigmatism and provides a perfectly flat field, ensuring images are crisp and detailed across the entire field of view, requiring minimal post-processing.

Robust Mechanical Structure

Built with a carbon fiber optical tube, the CDK20 is both durable and lightweight. Its design minimizes thermal expansion, ensuring minimal focus shift with temperature changes, which is ideal for extended observing sessions under diverse environmental conditions.

High-Performance Mirrors and Coatings

Utilizing fused silica mirrors, the CDK20 maintains precise optical alignment and exceptional surface accuracy, even during temperature fluctuations. The high-quality coatings improve light transmission and reduce stray light, optimizing the telescope's performance for specialized observational tasks.

Thermal Management

The CDK20 has cooling fans and a Delta-T ready system to achieve thermal equilibrium swiftly. These features help reduce air turbulence within the tube, thus minimizing image distortion and maintaining consistent imaging quality.

Integrated Dew Control

The telescope includes advanced dew prevention technology with heater pads controlled by PlaneWave’s software. This ensures optical surfaces remain free from condensation in humid conditions, thus maintaining clear and consistent imaging performance.

Application-Specific Benefits

Astrophotography

With its large image circle and exceptional field flatness, the CDK20 allows astrophotographers to capture expansive and breathtaking views of the cosmos with incredible detail and clarity.

Astronomy Research

The stable and precise imaging capabilities of the CDK20 make it an invaluable asset for academic institutions and observatories engaged in sophisticated astronomical research, including deep-sky surveys and detailed photometric studies.

Visual Observations

The CDK20 excels in visual observation, providing bright and clear views ideal for star parties and serious visual astronomy. Its large aperture and superior optical quality deliver stunning views of planetary, lunar, and deep-sky objects, making every viewing session a memorable experience. Here's the updated article adapted for the CDK17 based on the features and specifications from the provided product page:

Space Situational Awareness (SSA) and Space Domain Awareness (SDA)

The CDK20 also lends itself to Space Situational Awareness and Space Domain Awareness applications. Its capability to provide detailed observations can be essential for tracking and monitoring satellites and other space debris, contributing valuable data for space traffic management and safety initiatives.

Optical Systems

Secondary Mirror

Lens Group

Primary Mirror

CDK24’s Key Features

Large Aperture and Moderate Focal Ratio

The CDK24 features a substantial 610 mm aperture and a moderate f/6.5 focal ratio. This setup enhances its capability to capture deep-sky objects with remarkable detail, providing excellent light-gathering efficiency and a broad field of view for research and imaging.

Advanced Optical Design

Equipped with a state-of-the-art Corrected Dall-Kirkham optical system, the CDK24 offers exceptional image clarity. Its design eliminates off-axis coma and astigmatism and delivers a perfectly flat field, ensuring images are sharp and detailed across the entire field of view with minimal post-processing adjustments.

Robust Mechanical Structure

Constructed with a carbon fiber optical tube, the CDK24 is lightweight and durable. Its thermal expansion coefficient ensures minimal focus shift as temperatures change, making it ideal for prolonged observing sessions under varying environmental conditions.

High-Performance Mirrors and Coatings

Utilizing fused silica mirrors, the CDK24 maintains precise optical alignment and surface accuracy, even with temperature fluctuations. Its high-quality coatings enhance light transmission and reduce stray light, optimizing performance for specialized observational tasks.

Thermal Management

The CDK24 is equipped with cooling fans and a Delta-T ready system to achieve thermal equilibrium swiftly. These features help to minimize air turbulence within the tube, thus reducing image distortion and maintaining consistent imaging quality.

Integrated Dew Control

The telescope incorporates advanced dew prevention technology with heater pads controlled by PlaneWave’s software. This ensures that optical surfaces remain clear of condensation during humid conditions, thus maintaining clear and consistent imaging performance.

Application-Specific Benefits

Astrophotography

With its large image circle and exquisite field flatness, the CDK24 allows astrophotographers to capture expansive and breathtaking views of the cosmos with incredible detail and clarity.

Astronomy Research

The precise and stable imaging capabilities of the CDK24 make it an invaluable tool for academic institutions and observatories engaged in complex astronomical research, including deep-sky surveys and detailed photometric studies.

Visual Observations

The CDK24 excels in visual observation, offering bright and crisp views ideal for star parties and serious visual astronomy. The telescope's large aperture and superior optical quality provide stunning views of planetary, lunar, and deep-sky objects, making every viewing session a remarkable experience.

Space Situational Awareness (SSA) and Space Domain Awareness (SDA)

The CDK24 also lend itself to applications in Space Situational Awareness and Space Domain Awareness. Its capability to provide detailed observations can be essential for tracking and monitoring satellites and other space debris, contributing valuable data for space traffic management and safety initiatives.

Optical Systems

Secondary Mirror

Lens Group

Primary Mirror

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 Planewave CDK20 f/7.7 OTA 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!

PlaneWave CDK 12.5 Fused Silica

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) 12.5″ telescope was centered around performance and ease of use. The PlaneWave CDK 12.5 Fused Silica is an incredible breakthrough in telescope technology and produces no off-axis coma and no off-axis astigmatism. Additionally, the PlaneWave CDK 12.5 Fused Silica 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 CDK12.5 is an exceptional diffraction-limited telescope. CDK12.5 users can experience pinpoint stars edge-to-edge and a 70 x 70 arcminute field of view when using large camera sensors. When equipment fades into the background and simply performs, the astrophotography experience becomes even more fun and rewarding!

The PlaneWave CDK 12.5 Fused Silica 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 PlaneWave CDK 12.5 covers a 52 mm field of view without any field curvature, off-axis coma, or astigmatism. The instrument weight is 21kg and comes standard with the large capacity 2.75 inch Hedrick focuser.

Technology

The CDK Optical Design

The CDK telescope is based on a new optical design developed by Dave Rowe. The goal of the design is to make an affordable astrographic telescope with a large enough imaging plane to take advantage of the large format CCD cameras of today. Most telescope images degrade as you move off-axis from either coma, off-axis astigmatism, or field curvature. The CDK design suffers from none of these problems. The CDK is coma free, has no off-axis astigmatism, and has a flat field. The design is a simple and elegant solution to the problems posed above. The CDK consists of three components: an ellipsoidal primary mirror, a spherical secondary mirror and a lens group. All these components are optimized to work in concert in order to create superb pinpoint stars across the entire 52mm image plane.

Optical Performance

Shown are two simulations showing the CDK’s stunning performance. The first is a diffraction simulation and the second is a spot diagram. In both simulations the small squares are 9×9 microns, about the size of a CCD pixel. In the diffraction simulation the star images on axis and off-axis are nearly identical. In the spot diagram 21mm off-axis the spot size is an incredible 6 microns RMS diameter. This means stars across a 52 mm image circle are going to be pinpoints as small as the atmospheric seeing will allow.

Both of the simulations take into consideration a flat field, which is a more accurate representation of how the optics would perform on a flat CCD camera chip. For visual use some amount of field curvature would be allowed since the eye is able to compensate for a curved field. The diffraction simulation was calculated at 585nm. The spot diagram was calculated at 720, 585, and 430nm. Many companies show spot diagrams in only one wavelength, but you cannot see the chromatic performance with only one wavelength.

Comparison: CDK vs. Ritchey Chrétien

The simulations shown compares the optical performance of the CDK design to the Ritchey Chrétien (RC) design. The Ritchey design was popularized as an astroimaging telescope due to its use in many professional

observatories. Although very difficult and expensive to manufacture and align, the Ritchey is successful in eliminating many of the problems that plague many other designs, namely off-axis coma. However the Ritchey does nothing to eliminate the damaging effects of off-axis astigmatism and field curvature.

The CDK design tackles the off-axis coma problem by integrating a pair of correcting lenses into a two mirror design. The beauty is that this design also corrects for astigmatism and field curvature. Because the lenses are relatively close to the focal plane (unlike the Schmidt corrector plate found in various Schmidt Cassegrain designs), and because these lenses work together as a doublet, there is no chromatic aberration. The CDK offers a wide aberration-free, flat field of view that allows the user to take full advantage of the very large imaging chip cameras in the market place today.

Having an aberration free telescope design means nothing if the optics cannot be aligned properly. Many Ritchey owners never get to take full advantage of their instrument’s performance because the Ritchey is very difficult to collimate. Aligning the hyperbolic secondary mirror’s optical axis to the optical axis of the primary mirror is critical in the Ritchey design, and the tolerances are unforgiving. The secondary mirror of the CDK design is spherical. It has no optical axis and so the centering tolerance of the CDK secondary mirror is comparatively huge. With the help of some very simple tools, the CDK user will be able to set the secondary spacing, collimate the optics and begin enjoying the full performance potential the instrument has to offer within a few minutes.

The drastic difference in performance between the CDK and the RC is apparent. The biggest component that degrades the off-axis performance of the RC is the defocus due to field curvature. In many diagrams shown by RC manufacturers, the diagrams look better than this because they are showing a curved field. This is fine for visual use because the eye can compensate for some amount of curvature of field. But CCD arrays are flat and so in order to evaluate the performance a spot diagrams and/or diffraction simulations requires a flat field as shown.

PlaneWave CDK 12.5 Specifications

OPTICAL SYSTEM

SECONDARY MIRROR

PRIMARY MIRROR

LENS GROUP

SHIPPING

INCLUDED ACCESSORIES

Collimation and Spacing Instructions

PlaneWave CDK 14" Fused Silica

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.

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 six times lower than Borosilicate 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 high melting temperature (~1,600 degrees 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.

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:

PlaneWave CDK 14" Fused Silica Specifications

OPTICAL SYSTEM

SECONDARY MIRROR

PRIMARY MIRROR

LENS GROUP

STANDARD FEATURES

SHIPPING

NOTE: This product has a lengthy lead time. Please contact education@bintel.com.au for further information.