It is an affordable, high performance solution for astrophotography and visual use, with a large, flat focal surface that is perfect for modern, high resolution, ccd cameras. Shaw montana state university conics a conic is a surface of revolution formed by spinning a conic section around the axis. The cdk corrected dall kirkham telescope is based on a new optical design developed by dave rowe. Dks are normally intended for highpower planetary observing where only a small field is used. To assist cool down of the telescope, each model is fitted with three fans, all positioned behind the primary mirror. The paraboloids focal ratio fa corresponding to dallkirkhams angular field size is nearly independent of the secondary magnification m, and increases linearly with 1. It is diffraction limited across a 20mm image circle at the focal plane. 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. It is known as dall kirkham and, although with stronger coma than its classical counterparts, its mirrors are easier to make, and its miscollimation sensitivity is considerably lower than in either classical or aplanatic cassegrain, which makes it a viable practical alternative. Showcasing my planetary dall kirkham telescope rkblog. The reflecting telescope was invented in the 17th century, by isaac newton, as an alternative to the refracting telescope which, at that time, was a design that suffered from severe chromatic aberration.
My understanding is that the dk is simpler mirrors to produce which yields consistent quality, but as a consequence of that you get more coma off axis, but excellent on axis performance and easier collimation. Often you read about dall kirkham telescopes not always accurate and correct statements. A long focal length planetary dall kirkham telescope. The cdk14 covers a 70 mm field of view without any field curvature, offaxis coma, or astigmatism. Page 1 of 3 2025 corrected dall kirkham is this too insane. Cassegrain telescope design by fitting the asphericity between the two mirrors to control. Cdk stands for corrected dall kirkham corrected because a dall kirkham design by itself produces sharp images at the center of the field. Each orionopticsuk telescope is built on order, delivery time is about 40 days after order confirmation.
The modified dallkirkham telescope utilizes an elliptical primary and spherical secondary. This is a dall kirkham optical design with coatings that are optimized to transmit in infrared or ultra violet wavelengths. The cdk24 has a dual truss design, with 3 cooling fans for the back of the primary mirror and 8 fans for the front surface of the primary mirror. These are the formulas used to calculate the prescriptions of the primary and secondary mirrors for three types of cassegrain telescopes the dall kirkham, classical and ritcheychretien. This design uses a concave elliptical primary mirror and a convex spherical secondary. Optical system design s15 reflector telescopes joseph a. Plus some new software like latest astra image for sharpening and some. Takahashi collimation telescope tce0100 for rc, dall kirkham. The result is a modified dall kirkham telescope with integrated subaperture lens corrector, and significantly improved field quality. Accessories the telescope bag a complete and heavy duty, quick on and off, zippered cover air turbulence lower cover keeps warm body air away from light path 8 dall kirkham.
Dall kirkham telescope is based on a new optical design developed by dave rowe. On smaller telescopes, and camera lenses, the secondary is often mounted on an optically flat, optically clear glass plate that closes the telescope tube. Planewave instruments planewave store home 2242018. Dive in deep into the cdk optial design or see what makes direct drive.
The dall kirkham cassegrain telescopes design was created by horace dall in 1928 and took on the name in an article published in scientific american in 1930 following discussion between amateur astronomer allan kirkham and albert g. The telescope has a dual truss design, with 3 cooling fans for the back of the primary mirror and 8 fans for the front surface of the primary mirror. The cdk telescope design provides excellent imaging with large format ccd cameras while remaining superb for visual use. Installation and design services installation and design services new products. Takahashi collimation telescope tce0100 for rc, dall. The cdk optical design baader planetarium blog posts. History invented by master optician horace dall in 1928. The dall kirkham has a elliptic primary mirror and a spherical secondary mirror. Imaging dall kirkham idk quartz series telescopes quality. Cdk stands for corrected dallkirkham corrected because a dallkirkham design by itself produces sharp images at the center of. The image field optimised dall kirkham systems often have only one frame of 42 mm sometimes 50 mm, but with significant vignetting. Jodas java optical design and analysis software written by ivan krastev integrate all the features required to design and analyze telescope systems. Dallkirkham telescope is based on a new optical design developed by dave rowe.
Developed by planewave, the cdk corrected dallkirkham is a revolutionary new telescope optical system that was designed to excel at imaging on large format ccd cameras while remaining an excellent instrument for visual use. As with all the odk models, the odk10 is fitted as standard with an acu3s, 3 focuser to enable a strong focusing platform for a wide range of cameras. The paraboloids focal ratio f a corresponding to dall kirkham s angular field size is nearly independent of the secondary magnification m, and increases linearly with 1. Dallkirkham vs classical cassegrain posted in reflectors. The cdk corrected dall kirkham optical design is an innovative solution for unsurpassed astroimaging quality at an affordable price. First, realize that in the various cass designs, the mirrors require various amounts of. Northek cassegrain classical 250 mm f 15 dall kirkham. The optical design of the telescope bears explanation. The telescope has a dual truss design, with 3 cooling fans for the back of the primary mirror and 8. Indeed, whereas the cassegrain requires a difficult to execute secondary, the dall kirkam is content modestly with a spherical secondary mirror. The cdk optical design the cdk corrected dallkirkham telescope is based on a new optical design developed by dave rowe.
Telescope comes with either carbon fiber or aluminum tube. Dallkirkham telescopes expert service unbeatable prices. The corrected dallkirkham cdk the cassegrain reflector is a twomirror telescope design invented by laurent cassegrain in 1672. A quick numerical calculation using the mirror spacings for my 12. An interesting twomirror variant is one with the secondary left spherical. A standard dk telescope is usually designed as a very long focal length planetary scope. Oouk optimized dall kirkham telescope 250mm the oouk optimized dall kirkham telescope is a solid 250mm aperture offering of the utmost quality, operating at f6.
The dall kirkham uses a spherical secondary in combination with an elliptical primary. Takahashi mewlon 210 dall kirkham telescope camera concepts. The modified dallkirkham telescope utilizes an elliptical primary and spherical secondary mirror as in the conventional dallkirkham configuration, but also includes a lens group usually two or three lens elements ahead of the focal point to improve offaxis image quality. Optical layout of a corrected dallkirkham telescope. For the linear field size, the corresponding paraboloids focal ratio fl also increases linearly, with 1. The dallkirkham cassegrain telescopes design was created by horace dall in 1928 and took on the name in an article published in scientific american in 1930 following discussion between amateur astronomer allan kirkham and albert g. So, moving the secondary toward the primary should slightly increase the correction of a dall kirkham system in the system. The hubble corrected dallkirkham cdk optical configuration is a revolutionary optical design. The main drawback to the dall kirkham design is that the coma is even stronger than in a classical cassegrain, limiting the useful field of view. Show dallkirkham telescopes, takahashi dallkirkham telescopes, and takahashi mewlon dallkirkham telescopes. For the linear field size, the corresponding paraboloids focal ratio f l also increases linearly, with 1. The hubble corrected dall kirkham cdk optical configuration is a revolutionary optical design. The collimating telescope is simply attached to the 2 receptacle of the focuser by using the two optional adapters see recommended accessories. It is a telescope design software of the most popular telescope systems used by the amateur astronomers and telescope makers, including spot diagrams, ray fans, wave aberrations, diffraction analysis, optical layout, optimization, tolerancing, mirror testing and many other atm tools.
There are two options for a dall kirkham, either make it long focus to avoid the. The outstanding performance of the idk series is made possible through the convergence of modern design. These dall kirkham telescopes offer an optical quality unmatched by most modern scopes. The dallkirkham dk is a design variation on the classical cassegrain. The takahashi collimating telescope allows for a precise collimation of ritcheychretien, cassegrain, sc, dallkirkham telescopes prerequisite is a central mark on the secondary mirror. Planewave 17 cdk telescope with fused silica mirror opt. The dallkirkham uses a spherical secondary in combination with an elliptical primary. The simplest possible system in the family of catoptric and catadioptric correctors for the dall kirkham telescope, providing a flat field, fast relative aperture and improved optical quality over an extended field, is a single spherical mirror corrector. Takahashi dall kirkham telescopes offer stunning planetary views while coming in a large aperture, but compact instrument.
The optics, mechanical design, atmospheric conditions all of that has to line up. Being an open tube design and very short, cool down times are remarkably fast. Ingalls eventually published an article that mentioned the design, calling it the dallkirkham, and the name stuck. The dallkirkham has a elliptic primary mirror and a spherical secondary mirror. The imaging dall kirkham idk series is a premium line of f6. This is the most popular design in the world of professional reflector telescopes. The cdk corrected dallkirkham telescope is based on a new optical design developed by dave rowe. The planewave cdk design created to meet the demands of both the serious imager and visual observer, the planewave cdk corrected dallkirkham design far exceeds the offaxis performance of most commercial telescope designs, including the ritcheychretien. Show dall kirkham telescopes, takahashi dall kirkham telescopes, and takahashi mewlon dall kirkham telescopes. Planewave instruments technologies optical, mechanical.
The takahashi mewlon 210 at prime focus provides a focal length of 2415mm, focal ratio of f11. Modas stands for modern optical design and analysis software. A classical cassegrain telescope has a parabolic primary mirror and a hyperboloidal secondary mirror. Can anyone explain the difference in optical performance between these two designs. A comparative study and simulation of reflecting telescope. The planewave instruments cdk24pw24rc is a 24 inch 0. It is a telescope design software of the most popular telescope systems used by the. Dallkirkham vs classical cassegrain reflectors cloudy. Optical design software is used to minimize aberrations if given a well defined set.
Ngc 253 is a spiral galaxy in the sculptor constellation. General construction new design aluminum uchannel struts. Dall kirkham telescope combines refractorlike performance in a larger folded optic reflector design. These dallkirkham telescopes offer an optical quality unmatched by most modern scopes. Planewave interface pwi3 is the one software you will need to monitor and.
Ingalls, the magazines astronomy editor at the time. The main drawback to the dallkirkham design is that the coma is even stronger than in a classical cassegrain, limiting the useful field of view. Corrected, optimized, modified, opt has all the dk designs you need. These dallkirkham telescopes offer an optical quality unmatched by. Dall kirkham the dall kirkham cassegrain telescope s design was created by horace dall in 1928 and took on the name in an article published in scientific american in 1930 following discussion between amateur astronomer allan kirkham and albert g. The cdk14 is a lightweight carbonfiber truss design weighing less than 50lbs, with 3 cooling fans blowing air throughout the back of the telescope. The corrected dall kirkham cdk, uses a pair of corrector lenses ahead of the focal plane to eliminate basically all aberrations. The cdk corrected dallkirkham optical design is an innovative solution for unsurpassed astroimaging quality at an affordable price. Planewave pw observatory telescope 1meter observatory system planewave cdk700 observatory telescope.
So i was thinking about larger aperture scopes today. This is a dallkirkham optical design with coatings that are optimized to transmit in. Ingalls eventually published an article that mentioned the design, calling it the dall kirkham, and the name stuck. A reflecting telescope also called a reflector is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The consequence however is that also a 3d cad program was needed, and i. Ive come to the conclusion that i cannot build a dob larger than 18 or so because the eyepiece height would be too high or id need a paracorr ii and ethoses to use the thing, in addition to a very large and costly secondary mirror. It utilizes a space age carbon fiber sandwich sort of design for the actual optical tube.
The result is a relatively easytomake telescope that has exceptional performance. Optical layout of a corrected dall kirkham telescope the dall kirkham dk is a design variation on the classical cassegrain. The pressmancamichel uses a spherical primary mirror. Oouk optimized dall kirkham telescope 250mm best brands. Planewave pw observatory telescope 1meter observatory system. Planewave instruments is proud to introduce the cdk 24. By using an ellipsoidal primary mirror, it is possible to make a system free from spherical abberation by using a spherical secondary mirror, which is much easier to make and test than the hyperbolic secondary in. All major observatories and research institutions around the world work, and. Accordingly, the dall kirkham telescope would be the ultimate telescope, the photo machine for astrophotography with the best picture quality, the highest available field and the best star images. There are no refractive lens, only reflective components to the design. The odk10 is the most compact dall kirkham telescope by orionopticsuk and that, thanks to carbon fiber tube and weight of only 12 kg, can also be installed on compact and still portable mounts. Design, fabrication and integration of dome, telescope structure, optics, instruments, control and cooling.