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Ritchey-Chrétien & Dall-Kirkham Telescopes

Ritchey-Chrétien and corrected Dall-Kirkham telescopes are the long focal length workhorses of deep-sky imaging. Both use two mirrors to fold a long focal length into a compact tube, without the colour of a refractor or the coma of a Newtonian. They are the tool of choice for small galaxies, planetary nebulae and globular clusters, and the same family of design is used in most professional observatories.

We carry the iOptron Photron RC line from 6 to 16 inches, the Orion Optics UK ODK series from 10 to 24 inches in closed and truss tubes, and the SharpStar SCA260 Super Cassegrain.

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CA$1,649.00 - CA$1,649.00
CA$1,649.00
CA$1,649.00 - CA$1,649.00
CA$1,649.00

iOptron Photron 8" Ritchey-Chretien

200mm (8") Ritchey-Chretien Optical Design 1624mm Focal Length at f/8 Coma-Free Ritchey-Chretien Optics 2" 10:1 Dual-Speed Crayford Focuser Losman...

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CA$1,649.00 - CA$1,649.00
CA$1,649.00
CA$1,649.00 - CA$1,649.00
CA$1,649.00
CA$781.00 - CA$781.00
CA$781.00
CA$781.00 - CA$781.00
CA$781.00

iOptron Photron 6" Ritchey-Chretien

150mm (6") Ritchey-Chretien Optical Design 1370mm Focal Length f/9 Focal Ratio 10:1 Dual-Speed 2" Crayford Focuser 12 lbs Tube Weight Descripti...

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CA$781.00 - CA$781.00
CA$781.00
CA$781.00 - CA$781.00
CA$781.00
CA$6,461.00 - CA$6,461.00
CA$6,461.00
CA$6,461.00 - CA$6,461.00
CA$6,461.00

SharpStar SCA260 V2 260mm f/5 Super Cassegrain Astrograph

260mm (10.2") Aperture Aspherical Primary Mirror 1300mm Focal Length at a fast f/5 Focal Ratio Massive 80mm Corrected Image Circle for Large Forma...

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CA$6,461.00 - CA$6,461.00
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CA$6,461.00 - CA$6,461.00
CA$6,461.00
CA$9,379.00 - CA$9,379.00
CA$9,379.00
CA$9,379.00 - CA$9,379.00
CA$9,379.00

iOptron Photron 14" Ritchey-Chretien

14" (355mm) Ritchey-Chretien Optical Design 2848mm Focal Length at f/8 Carbon Fiber Truss Tube for Thermal Stability Heavy-duty 3" Dual-Speed 10:1...

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CA$9,379.00 - CA$9,379.00
CA$9,379.00
CA$9,379.00 - CA$9,379.00
CA$9,379.00
Orion Optics UK ODK24Tr Truss Optical Tube Assembly
CA$118,331.00 - CA$118,331.00
CA$118,331.00
CA$118,331.00 - CA$118,331.00
CA$118,331.00

Orion Optics UK ODK24Tr Truss Optical Tube Assembly

Optimized Dall-Kirkham (ODK) Optical Design Corrected, Coma-Free Flat Field for Imaging Open Truss Tube for Thermal Stability and Rigidity Hand-Fi...

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CA$118,331.00 - CA$118,331.00
CA$118,331.00
CA$118,331.00 - CA$118,331.00
CA$118,331.00
Orion Optics UK ODK20Tr Optical tube assembly
CA$53,215.00 - CA$53,215.00
CA$53,215.00
CA$53,215.00 - CA$53,215.00
CA$53,215.00

Orion Optics UK ODK20Tr Optical tube assembly

500mm truss-tube Dall-Kirkham f/6.8 carbon-fibre-sandwich optics Open truss for shorter packed length Built to order in the UK Description Spec...

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CA$53,215.00 - CA$53,215.00
CA$53,215.00
CA$53,215.00 - CA$53,215.00
CA$53,215.00
Orion Optics UK ODK18Tr Truss Optical Tube Assembly
CA$43,433.00 - CA$43,433.00
CA$43,433.00
CA$43,433.00 - CA$43,433.00
CA$43,433.00

Orion Optics UK ODK18Tr Truss Optical Tube Assembly

Optimized Dall-Kirkham (ODK) Optical Design Open Truss Tube Framework Primary and Secondary Mirrors by Orion Optics UK Engineered for Astrophotogr...

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CA$43,433.00 - CA$43,433.00
CA$43,433.00
CA$43,433.00 - CA$43,433.00
CA$43,433.00
Orion Optics UK ODK16Tr Truss Optical Tube Assembly
CA$27,897.00 - CA$27,897.00
CA$27,897.00
CA$27,897.00 - CA$27,897.00
CA$27,897.00

Orion Optics UK ODK16Tr Truss Optical Tube Assembly

400mm (16") Optimized Dall-Kirkham Optics 2720mm Focal Length (f/6.8) >52mm Fully Corrected and Illuminated Image Circle 2.4µm On-Axis Spot Siz...

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CA$27,897.00 - CA$27,897.00
CA$27,897.00
CA$27,897.00 - CA$27,897.00
CA$27,897.00
Orion Optics UK ODK14Tr Truss Optical Tube Assembly
CA$20,225.00 - CA$20,225.00
CA$20,225.00
CA$20,225.00 - CA$20,225.00
CA$20,225.00

Orion Optics UK ODK14Tr Truss Optical Tube Assembly

350mm (14") Optimized Dall-Kirkham Optics 2380mm Focal Length (f/6.8) >52mm Fully Illuminated and Corrected Image Circle 2.1µm On-Axis Spot Siz...

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CA$20,225.00 - CA$20,225.00
CA$20,225.00
CA$20,225.00 - CA$20,225.00
CA$20,225.00
Orion Optics UK ODK12Tr Truss Optical Tube Assembly
CA$16,006.00 - CA$16,006.00
CA$16,006.00
CA$16,006.00 - CA$16,006.00
CA$16,006.00

Orion Optics UK ODK12Tr Truss Optical Tube Assembly

300mm (12") Optimized Dall-Kirkham Astrograph 2040mm Focal Length (f/6.8) >52mm Flat, Corrected Image Circle 1.8µm On-Axis Spot Size Carbon Fib...

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CA$16,006.00 - CA$16,006.00
CA$16,006.00
CA$16,006.00 - CA$16,006.00
CA$16,006.00
Orion Optics UK ODK10Tr Truss Optical Tube Assembly
CA$11,316.00 - CA$11,316.00
CA$11,316.00
CA$11,316.00 - CA$11,316.00
CA$11,316.00

Orion Optics UK ODK10Tr Truss Optical Tube Assembly

250mm (10-inch) Optimized Dall-Kirkham optics 1700mm focal length at a native f/6.8 focal ratio 50mm fully corrected, flat image circle for large ...

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CA$11,316.00 - CA$11,316.00
CA$11,316.00
CA$11,316.00 - CA$11,316.00
CA$11,316.00
Orion Optics UK ODK16 Optical Tube Assembly
CA$25,212.00 - CA$25,212.00
CA$25,212.00
CA$25,212.00 - CA$25,212.00
CA$25,212.00

Orion Optics UK ODK16 Optical Tube Assembly

400mm (16") Primary Mirror Diameter 2720mm Focal Length at f/6.8 Corrected Dall-Kirkham Optical Design >52mm Flat Field Image Circle Carbon Fib...

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CA$25,212.00 - CA$25,212.00
CA$25,212.00
CA$25,212.00 - CA$25,212.00
CA$25,212.00
Orion Optics UK ODK14 Optical Tube Assembly
CA$18,116.00 - CA$18,116.00
CA$18,116.00
CA$18,116.00 - CA$18,116.00
CA$18,116.00

Orion Optics UK ODK14 Optical Tube Assembly

Primary Mirror Diameter: 350mm Focal Ratio: f/6.8 Corrected Image Circle: >52mm Tube Material: Carbon Fibre Sandwich Back Focus: 210mm Tu...

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CA$18,116.00 - CA$18,116.00
CA$18,116.00
CA$18,116.00 - CA$18,116.00
CA$18,116.00
Orion Optics UK ODK12 Optical Tube Assembly
CA$13,321.00 - CA$13,321.00
CA$13,321.00
CA$13,321.00 - CA$13,321.00
CA$13,321.00

Orion Optics UK ODK12 Optical Tube Assembly

300mm (12") Optimised Dall-Kirkham Optics 2040mm Focal Length at a fast f/6.8 Focal Ratio Covers a greater than 52mm flat imaging circle Delivers ...

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CA$13,321.00 - CA$13,321.00
CA$13,321.00
CA$13,321.00 - CA$13,321.00
CA$13,321.00
Orion Optics UK ODK10 Optical Tube Assembly
CA$8,334.00 - CA$8,334.00
CA$8,334.00
CA$8,334.00 - CA$8,334.00
CA$8,334.00

Orion Optics UK ODK10 Optical Tube Assembly

250mm (10") Corrected Dall-Kirkham Optics 1700mm Focal Length at f/6.8 50mm Fully Corrected Flat Image Circle 3.5μm On-Axis Spot Size Carbon Fibre...

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CA$8,334.00 - CA$8,334.00
CA$8,334.00
CA$8,334.00 - CA$8,334.00
CA$8,334.00
iOptron Photron™ 10-inch Ritchey-Chrétien Telescope (RC10) 3'' Focuser
CA$4,043.00 - CA$4,043.00
CA$4,043.00
CA$4,043.00 - CA$4,043.00
CA$4,043.00

iOptron Photron™ 10-inch Ritchey-Chrétien Telescope (RC10) 3'' Focuser

250mm (10-inch) Ritchey-Chrétien Optical Design 2000mm Focal Length at f/8 0.46 arc second Resolving Power 3-inch Dual Speed Focuser 35 lb Steel T...

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CA$4,043.00 - CA$4,043.00
CA$4,043.00
CA$4,043.00 - CA$4,043.00
CA$4,043.00
CA$12,319.00 - CA$12,319.00
CA$12,319.00
CA$12,319.00 - CA$12,319.00
CA$12,319.00

iOptron Photron 16" Ritchey-Chretien

16" (406mm) Aperture 3248mm Focal Length f/8 Focal Ratio Ritchey-Chretien Optical Design Carbon Fiber Truss Tube 3" 10:1 Dual-Speed Focuser Des...

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CA$12,319.00 - CA$12,319.00
CA$12,319.00
CA$12,319.00 - CA$12,319.00
CA$12,319.00
CA$5,821.00 - CA$5,821.00
CA$5,821.00
CA$5,821.00 - CA$5,821.00
CA$5,821.00

iOptron Photron 12" Ritchey-Chretien

12" (304mm) Ritchey-Chretien Optics 2432mm Focal Length f/8 Focal Ratio Carbon Fiber Truss Tube Design 3" Dual-Speed 10:1 Crayford Focuser 53 lb O...

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CA$5,821.00 - CA$5,821.00
CA$5,821.00
CA$5,821.00 - CA$5,821.00
CA$5,821.00
CA$4,477.00 - CA$4,477.00
CA$4,477.00
CA$4,477.00 - CA$4,477.00
CA$4,477.00

iOptron Photron 10" Ritchey-Chretien

10" (254mm) Ritchey-Chretien Optical Design 2032mm Focal Length f/8 Focal Ratio Carbon Fiber Truss Tube for Thermal Stability 3-inch, 10:1 Dual-Sp...

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CA$4,477.00 - CA$4,477.00
CA$4,477.00
CA$4,477.00 - CA$4,477.00
CA$4,477.00

RC, DK and Corrected DK

  • Ritchey-Chrétien: Two hyperbolic mirrors remove coma. The field is still curved, so a flattener is recommended for APS-C sensors and larger.
  • Corrected Dall-Kirkham (ODK): An elliptical primary and spherical secondary with a lens corrector near focus. Gives a flat, coma-free field over a large sensor and is easier to collimate than an RC.
  • Super Cassegrain (SCA): SharpStar's design adds correcting optics for a faster focal ratio and wide flat field.
  • Truss or closed tube: Truss tubes are lighter and cool faster. Closed tubes resist stray light and dew better for portable use.

What These Telescopes Demand

At 1600 to 3000 mm of focal length, tracking errors and seeing are magnified. Expect to use off-axis guiding, a mount with real margin and an electronic focuser with temperature compensation. Collimation is precise work, especially on RC designs.

What We Plan With You

  • Image scale: Long focal length with small pixels oversamples most skies. We check your camera and suggest binning or a reducer if needed.
  • Mount and guiding: We size the mount for the tube's length and weight and plan off-axis guiding.
  • Corrector and spacing: We confirm the flattener or reducer and its exact back-focus.
  • Collimation support: We explain a reliable routine for your design so you are not chasing it every night.

RC and Dall-Kirkham Telescopes: Frequently Asked Questions

Is an RC good for a first imaging telescope?

It is not the easiest start. Long focal length is unforgiving. Most imagers learn on a small refractor, then add an RC for galaxies.

Can I observe visually with an RC?

Yes, but the large central obstruction lowers contrast on planets. These are designed primarily for imaging.

How often does an RC need collimation?

A well-built RC holds collimation for months if it is not knocked around. A quick star test each session tells you if anything moved.

Ready to image galaxies at long focal length?

Send us your mount, camera and sky conditions. We will tell you which tube will work for you.