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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.
Apertures available are:
ODK10: 250mm
ODK12: 300mm
ODK14: 350mm
ODK16: 400mm
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. (see photo opposite)
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.
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.
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Scroll down for Model Specifications
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.
Mounts for ODK:
Prices quoted are for Optical Tube Assembly only. Carbon Tubes come complete with 3" Focuser, Finder, Dovetail and Supports.
We recommend the following Mounts for ODK Tubes:
ODK12: Vixen SXD
Specification |
ODK10 |
ODK12 |
ODK14 |
ODK16 |
Aperture |
250mm |
300mm |
350mm |
400mm |
Focal length |
1700mm |
2040mm |
2380mm |
2720mm |
Focal Ratio |
f6.8 |
f6.8 |
f6.8 |
f6.8 |
Tube Weight |
9.5kg |
approximately 15kg |
approximately 22kg |
approximately 30kg |
Tube Diameter |
300mm |
350mm |
400mm |
450mm |
TubeLength |
475mm |
TBA |
TBA |
TBA |
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 |
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.