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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.
ODK10rearThe 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.

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Click here for Electronic Drive Downloads.

Optimised Dall-Kirkam Tube Units Only

ODK10 Optimised Dall-Kirkham OTA

£4260

ODK12 Optimised Dall-Kirkham OTA

£5950

ODK14 Optimised Dall-Kirkham OTA

£7420

ODK16 Optimised Dall-Kirkham OTA

£8660

Electronic Drive* / Variable micro speed Controller

£480

Finder 9x50 black. Straight view. Complete

£88

Finder 9x50 black. Right Angled view. Complete

£98

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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.
mount plate/dovetail)

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
alum. cell

Honeycombe CNC machined
alum. cell

Honeycombe CNC machined
alum. cell

Honeycombe CNC machined
alum. cell

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

Click to view ODK 10
Graphs / Diagrams

Click to view ODK 12
Graphs / Diagrams

Click to view ODK 14
Graphs / Diagrams

Click to view ODK 16
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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lightbulb" 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 Fixing adjustment rings. 85mm diameter

all (except 5 & 10mm) have internal baffles to help remove or eliminate stray light. They take up the following in the back focal distance (BFD) £85 each [Stack of rings shown]

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5mm FAR85-5

10mm FAR85-10

15mm FAR85-15

20mm FAR85-20

25mm FAR85-25

40mm FAR85-40

50mm FAR85-50

ODK Specified Adaptors

Adaptors down from 85mm to camera. filter wheel or adaptive optics (£180) each) using up to 15mm BFD. Email us with requirements to john@orionoptics.co.uk mark email heading ODK 85mm to camera fitting.

ODK Adaptors down from 85mm to specified

Adaptors down from 85mm to specified internal diameter 3", 2" or 1 1/4" using up 10mm in BFD (£150 each)

FAR 85 - 1 1/4 inch

FAR 85 - 2 inch

FAR 85 - 3 inch

ODK Adaptors down from 3" to 2"

Adaptors down from 3" to 2" push fit with brass compression ring using up 10mm in BFD (£130 each)

ADT 3 inch - 2 inch

ODK Adaptors down from 2" to 1 1/4"

Adaptors down from 2" to 1 1/4" using up 10mm in BDF (£25 each)

ADT 2 - 1 1/4 inch

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Please Note: The OC2 Crayford takes up 58mm of BFD. It also has 15mm of movement on the drawtube. (See example below)

Example  (BFD back focal distance)
ODK12 BFD is 218mm - (58mm OC2) - (7.5mm half the movement of draw tube) - (120mm camera equipment) = 33mm remaining for adaptors.
Adaptors to use as an example would be:
FAR85-15 and 1 x (ODK specified adaptor BFD15mm) leaves 3mm to be absorbed in focusing with the OC2.

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ODK Package (OTA + Mount)

Click on model to view options

ODK10 (f6.8)

ODK12 (f6.8)

ODK14 (f6.8)

ODK16 (f6.8)

* This is a nominal distance and may vary by several mm due to slight production radii tolerances.

Upper
Support
Plate

Lower
Support Plate

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