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For those who prefer a catadioptric telescope which is exceptional both for photographic and visual use, we have introduced our Optimised Dall-Kirkham series, designated ODK.
Models available are: ODK10, ODK12, ODK14 and ODK16
The full range is based on a focal ratio of f6.8, fast enough for some superb deep sky photo-visual use and, still have enough focal length for high resolution planetary work both visual and CCD applications.
The tube is constructed from Carbon Fibre sandwich design. Very, very strong to avoid flexing and, zero expansion to ensure the focal plane does not change over long photographic exposures. Being an open tube design and very short, cool down times are remarkably fast.
To assist cool down of the telescope, each model is fitted with three fans, all positioned behind the primary mirror.
Exact focusing across the ODK range is achieved with our newly introduced Precision 3” Crayford Focuser featuring a 10:1 reduction drive included as standard and, as an option; we can include our electronic drive system with variable speed focusing control. Good images need good optics, all fitted in reliable, stable and precise engineering.
Note: Customers with heavier than normal (4kg+) CCD equipment, please see
AG page for possible uprated focusing possibilities.
The mirrors in our ODK range are hand figured to Lambda/8 or better.
Both mirrors are supplied with our enhanced Hilux reflective coatings giving up to 25% brighter images than conventional coatings.
A full Zygo report of the main mirror is issued from our optical laboratory and is provided with each telescope. The combination of the mirrors and lenses in the ODK yield typically a 1/6PV wavefront, higher accuracies can be achieved by meticulous hand figuring of the individual optical components to achieve up to 1/10PV, ask for details.
Buy this model as an Optical Tube Only (OTA) or Buy Tube and Mount as a Package from the selection below.
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To allow precise collimation, both primary and secondary mirrors can be collimated.
Computer optimised designs ensure both mirrors and corrector lenses can be brought to collimation easily and stay firmly in alignment. All ODK optical tubes are fitted with a dovetail plate.
If your preference is tube rings, we can fit these as an option.
ODK Std Equipment:
Prices quoted are for Optical Tube Assembly only. Carbon Tubes come complete with 3" Focuser, two support plates to which dovetails (supplied) or equipment, can be fixed as per your requirement.
NOTES: Please see Adaptors and Adjustment Rings below to achieve focus with all your equipment.
(If we have not got it on site please ask as we have state of the art CNC machines and will be able to accommodate you).
OC2 focusers on ODK models are designed to accept equipment up to and including 4 kg. If heavier equipment is planned, we have several options available to carry up to 7kg. Please contact us for detailed options.

Click here for Electronic Drive Downloads.
Specification |
ODK10 |
ODK12 |
ODK14 |
ODK16 |
Primary mirror diameter |
250mm |
300mm |
350mm |
400mm |
Focal length |
1700mm |
2040mm |
2380mm |
2720mm |
Focal Ratio |
f6.8 |
f6.8 |
f6.8 |
f6.8 |
Tube Weight (inc. |
12kg |
19kg |
26kg |
36kg |
Tube Diameter |
300mm |
350mm |
400mm |
450mm |
Tube Length |
475mm |
615mm |
700mm |
820mm |
BFD (Back Focal Distance) from cell face* |
213mm |
218mm |
210mm |
216mm |
Tube Material |
Carbon fibre sandwich |
Carbon fibre sandwich |
Carbon fibre sandwich |
Carbon fibre sandwich |
Secondary Size |
96mm |
120mm |
136mm |
152mm |
Mirror Cell |
Honeycombe CNC machined |
Honeycombe CNC machined |
Honeycombe CNC machined |
Honeycombe CNC machined |
Focuser |
3" Crayford with 10:1 reduction |
3" Crayford with 10:1 reduction |
3" Crayford with 10:1 reduction |
3" Crayford with 10:1 reduction |
Corrector Design |
Multi coated 3 lens |
Multi coated 3 lens |
Multi coated 3 lens |
Multi coated 3 lens |
Flat Field Size |
50mm |
>52mm |
>52mm |
>52mm |
Spot Size on Axis |
3.5µ |
1.8µ |
2.1µ |
2.4µ |
Spot Size at Field Edge |
6.2µ |
5.6µ |
5.6µ |
6.0µ |
Mirror / Tube Cooling |
3 Controllable fans. Heaters optional |
3 Controllable fans. Heaters optional |
3 Controllable fans. Heaters optional |
3 Controllable fans. Heaters optional |
Attachment Method |
CNC machined alum. dovetail with supports |
CNC machined alum. dovetail with supports |
CNC machined alum. dovetail with supports |
CNC machined alum. dovetail with supports |
Spec. Graphs / Diagrams |
To produce the photo-visual wide, flat field of the ODK range, we have designed and fitted integrally, a corrector lens system. which ensure both colour correction, coma and spherical aberration are optimised to achieve almost a perfect photographic and visual field. Adequate back focus allows all modern CCD cameras to be used with auxiliary equipment. Multi layer anti reflection coatings are applied to all lens surfaces to maintain brighter images.
CNC machined mono construction secondary spider and trim ensures stability in collimation. Our unique collimation adjustment system enables perfect collimation of the secondary mirror to be achieved, quickly and reliably.
* Electric focuser is Ascom stepper motor driven.
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" On first light with the ODK12, I was absolutely amazed at the sharpness and clarity of the stars right across the field. I pointed the telescope to several of my favourite close doubles and was delighted at the colour rendition and separation which the optics could provide. I recognised instantly that I was dealing with an absolutely superb optical system – without doubt one of the best, if not the best that I have ever used. The Moon was in the sky and roughly 20 degrees or so from the Dumbell Nebula and I took a series of eight images with no flats or darks. The image produced was astounding in detail and colour. Despite being my very first attempt, It is one of the finest images I have taken from a very poor coastal, light polluted site. I am absolutely delighted with the performance of this telescope. The manufacturing quality is of the highest order with high levels of engineering evident in every component."
Andy McCrea, N. Ireland
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ODK Package (OTA + Mount) |
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* This is a nominal distance and may vary by several mm due to slight production radii tolerances. |
Upper
Support
Plate
Lower
Support Plate