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Refractors

Refractors

Refractors earn their following through consistency. A sealed lens system holds collimation indefinitely, cools quickly, gives high-contrast views without a central obstruction, and — in modern apochromatic form — produces the clean, round stars that make wide-field astrophotography look effortless. David Astro carries refractors in Canada, from compact 50 mm travel astrographs to large apochromatic triplets, shipping from Canadian stock.

We image with refractors under Canadian skies and can speak to the practical differences between doublets and triplets, and between glass types, in terms of what actually shows in a finished image rather than what appears on a specification sheet.

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CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$1,679.00 - CA$1,679.00
CA$1,679.00

Askar 103APO f/6.8 Triplet

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103mm Aperture Triplet Air-Spaced APO Objective 700.4mm Focal Length f/6.8 Native Focal Ratio Includes One ED Glass Element for Superb Color Corre...

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CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$3,219.00 - CA$3,219.00
CA$3,219.00
CA$3,219.00 - CA$3,219.00
CA$3,219.00

Askar 107PHQ f/7 Quadruplet APO

ASK-107PHQ
1 in stock

107mm Quadruplet APO Optical Design 749mm Focal Length at f/7 44mm Corrected Image Circle for Full-Frame Sensors Integrated Field Flattener for Si...

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CA$3,219.00 - CA$3,219.00
CA$3,219.00
CA$3,219.00 - CA$3,219.00
CA$3,219.00
CA$2,379.00 - CA$2,379.00
CA$2,379.00
CA$2,379.00 - CA$2,379.00
CA$2,379.00

Askar 120APO f/7 Triplet

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120mm Aperture Triplet Air-Spaced APO Objective Includes one ED Glass Element for Superb Color Correction 840mm Focal Length at a Native f/7 Focal...

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CA$2,379.00 - CA$2,379.00
CA$2,379.00
CA$2,379.00 - CA$2,379.00
CA$2,379.00
CA$4,899.00 - CA$4,899.00
CA$4,899.00
CA$4,899.00 - CA$4,899.00
CA$4,899.00

Askar 130PHQ f/7 Quadruplet APO

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130mm Aperture Quadruplet APO Optics 1000mm Focal Length at f/7.7 Built-in Field Flattener 60mm Corrected Image Circle Total Assembled Weight of 1...

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CA$4,899.00 - CA$4,899.00
CA$4,899.00
CA$4,899.00 - CA$4,899.00
CA$4,899.00
Askar 131F Flat-Field APO Refractor
CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$2,799.00 - CA$2,799.00
CA$2,799.00

Askar 131F Flat-Field APO Refractor

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131mm Aperture f/7.5 Focal Ratio Quadruplet Air-Spaced APO Optical Design Includes one ED Glass Element 44mm Full-Frame Image Circle Integrated Fi...

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CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$3,499.00 - CA$3,499.00
CA$3,499.00
CA$3,499.00 - CA$3,499.00
CA$3,499.00

Askar 140APO f/7 Triplet

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2 in stock

140mm Aperture 980mm Focal Length f/7 Focal Ratio Air-Spaced Triplet APO with ED Glass OTA Weight: 9.2kg 125mm Retractable Rear Tube Descriptio...

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CA$3,499.00 - CA$3,499.00
CA$3,499.00
CA$3,499.00 - CA$3,499.00
CA$3,499.00
Askar 151PHQ f/7 Quadruplet Astrograph
CA$6,299.00 - CA$6,299.00
CA$6,299.00
CA$6,299.00 - CA$6,299.00
CA$6,299.00

Askar 151PHQ f/7 Quadruplet Astrograph

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151mm Aperture Quadruplet APO Optics 1057mm Focal Length at f/7 Integrated Flattener for a 60mm Image Circle Includes Two ED Glass Elements for Co...

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CA$6,299.00 - CA$6,299.00
CA$6,299.00
CA$6,299.00 - CA$6,299.00
CA$6,299.00
CA$5,383.00 - CA$5,383.00
CA$5,383.00
CA$5,383.00 - CA$5,383.00
CA$5,383.00

Askar 160APO f/7 Triplet

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160mm Aperture Triplet Air-Spaced APO Objective 1120mm Focal Length at f/7 Includes One ED Glass Element for Color Correction Retractable Dew Shie...

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CA$5,383.00 - CA$5,383.00
CA$5,383.00
CA$5,383.00 - CA$5,383.00
CA$5,383.00
CA$7,391.00 - CA$7,391.00
CA$7,391.00
CA$7,391.00 - CA$7,391.00
CA$7,391.00

Askar 185APO f/7 Triplet

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1 in stock

185mm Aperture Triplet APO Objective 1295mm Focal Length at f/7 Includes one ED Glass Element for Color Correction 95mm Retractable Rear Tube for ...

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CA$7,391.00 - CA$7,391.00
CA$7,391.00
CA$7,391.00 - CA$7,391.00
CA$7,391.00
Askar 203APO f/7 Triplet APO Refractor
CA$12,011.00 - CA$12,011.00
CA$12,011.00
CA$12,011.00 - CA$12,011.00
CA$12,011.00

Askar 203APO f/7 Triplet APO Refractor

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203mm Aperture Triplet Air-Spaced APO Objective 1421mm Focal Length at f/7 Includes one ED (Extra-Low Dispersion) Glass Element Retractable Tube D...

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CA$12,011.00 - CA$12,011.00
CA$12,011.00
CA$12,011.00 - CA$12,011.00
CA$12,011.00
CA$419.00 - CA$419.00
CA$419.00
CA$419.00 - CA$419.00
CA$419.00

Askar 50P f/3.8 Quadruplet APO Telescope

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5 in stock

50mm Aperture Quadruplet APO Optics Ultra-Fast f/3.8 Focal Ratio 190mm Focal Length Natively Flat Field for APS-C Sensors Standard 55mm Back Focus...

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CA$419.00 - CA$419.00
CA$419.00
CA$419.00 - CA$419.00
CA$419.00
Askar 60F Flat-Field Astrograph
CA$699.00 - CA$699.00
CA$699.00
CA$699.00 - CA$699.00
CA$699.00

Askar 60F Flat-Field Astrograph

ASK-ASAPO60F
1 in stock

60mm Aperture Quadruplet APO Optics 408mm Focal Length f/6.8 Native Focal Ratio 44mm Full-Frame Image Circle Integrated Field Flattener 2.86kg Gro...

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CA$699.00 - CA$699.00
CA$699.00
CA$699.00 - CA$699.00
CA$699.00
Askar 65PHQ f/6.4 Quintuplet Flat-Field Astrograph
CA$1,259.00 - CA$1,259.00
CA$1,259.00
CA$1,259.00 - CA$1,259.00
CA$1,259.00

Askar 65PHQ f/6.4 Quintuplet Flat-Field Astrograph

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65mm Aperture Quintuplet APO Optical Design 416mm Focal Length at f/6.4 Built-in Field Flattener with 44mm Image Circle 2.8kg Total Weight Includi...

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CA$1,259.00 - CA$1,259.00
CA$1,259.00
CA$1,259.00 - CA$1,259.00
CA$1,259.00
CA$923.00 - CA$923.00
CA$923.00
CA$923.00 - CA$923.00
CA$923.00

Askar 71F Quadruplet Flat-Field APO f/6.9

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71mm Aperture Quadruplet APO Optical Design 490mm Focal Length at f/6.9 44mm Full-Frame Corrected Image Circle Integrated Field Flattener 3.0kg To...

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CA$923.00 - CA$923.00
CA$923.00
CA$923.00 - CA$923.00
CA$923.00
CA$559.00 - CA$559.00
CA$559.00
CA$559.00 - CA$559.00
CA$559.00

Askar 80ED f/7 Doublet

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1 in stock

560mm Focal Length f/7 Focal Ratio Triplet Objective with ED Glass APS-C Corrected Image Circle 55mm Back Focus 0.42kg Weight Description FAQ S...

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CA$559.00 - CA$559.00
CA$559.00
CA$559.00 - CA$559.00
CA$559.00
CA$2,099.00 - CA$2,099.00
CA$2,099.00
CA$2,099.00 - CA$2,099.00
CA$2,099.00

Askar 80PHQ f/7 Quadruplet APO

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80mm Aperture 600mm Focal Length (f/7.5) Quadruplet APO Optics with 2 ED Elements 44mm Full-Frame Image Circle 3.9kg Optical Tube Weight Descri...

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CA$2,099.00 - CA$2,099.00
CA$2,099.00
CA$2,099.00 - CA$2,099.00
CA$2,099.00
Askar 91F Flat-Field Astrograph
CA$1,399.00 - CA$1,399.00
CA$1,399.00
CA$1,399.00 - CA$1,399.00
CA$1,399.00

Askar 91F Flat-Field Astrograph

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91mm Aperture Quadruplet APO Optics 609mm Focal Length at f/6.7 44mm Full-Frame Corrected Image Circle Integrated Field Flattener Design 3.92kg Ne...

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CA$1,399.00 - CA$1,399.00
CA$1,399.00
CA$1,399.00 - CA$1,399.00
CA$1,399.00
CA$461.00 - CA$461.00
CA$461.00
CA$461.00 - CA$461.00
CA$461.00

Askar FMA135 135mm f/4.5 APO Lens

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1 in stock

135mm Focal Length f/4.5 Focal Ratio 30mm Aperture Sextuplet APO Optical Design 280g Total Weight Description FAQ Specifications In the Box Dow...

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CA$461.00 - CA$461.00
CA$461.00
CA$461.00 - CA$461.00
CA$461.00
CA$615.00 - CA$615.00
CA$615.00
CA$615.00 - CA$615.00
CA$615.00

Askar FMA180 Pro 180mm f/4.5 APO Full Frame Lens

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1 in stock

40mm Aperture Sextuplet APO Lens 180mm Focal Length at a Fast f/4.5 44mm Image Circle for Full-Frame Sensors Standard 55mm Back Focus with M48x0.7...

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CA$615.00 - CA$615.00
CA$615.00
CA$615.00 - CA$615.00
CA$615.00
CA$1,329.00 - CA$1,329.00
CA$1,329.00
CA$1,329.00 - CA$1,329.00
CA$1,329.00

Askar FRA300 Pro 60mm f/5 Quintuplet APO

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60mm Aperture Quintuplet APO Astrograph 300mm Focal Length at a Fast f/5 Focal Ratio 44mm Full-Frame Image Circle Integrated Petzval Corrector Des...

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CA$1,329.00 - CA$1,329.00
CA$1,329.00
CA$1,329.00 - CA$1,329.00
CA$1,329.00
CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$1,679.00 - CA$1,679.00
CA$1,679.00

Askar FRA400 72mm f/5.6 Quintuplet APO

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72mm Aperture Quintuplet APO Lens 400mm Focal Length at f/5.6 44mm Full-Frame Image Circle 140mm Available Back Focus 3" Rack-and-Pinion Focuser w...

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CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$1,679.00 - CA$1,679.00
CA$1,679.00
CA$1,253.00 - CA$1,253.00
CA$1,253.00
CA$1,253.00 - CA$1,253.00
CA$1,253.00

Askar FRA400C 72mm f/5.6 Quintuplet APO

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72mm Aperture Quintuplet APO Optics 400mm Focal Length at f/5.6 Covers a 44mm Full-Frame Image Circle Integrated 17-Blade Aperture (f/5.6-f/22) 2....

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CA$1,253.00 - CA$1,253.00
CA$1,253.00
CA$1,253.00 - CA$1,253.00
CA$1,253.00
CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$2,799.00 - CA$2,799.00
CA$2,799.00

Askar FRA500 90mm f/5.6 Quintuplet APO

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90mm Aperture Quintuplet APO Optics 500mm Focal Length at f/5.6 Massive 55mm Flat-Field Image Circle Includes Two ED Glass Elements Total Assemble...

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CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$2,799.00 - CA$2,799.00
CA$2,799.00
CA$3,639.00 - CA$3,639.00
CA$3,639.00
CA$3,639.00 - CA$3,639.00
CA$3,639.00

Askar FRA600 108mm f/5.6 Quintuplet APO

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108mm Aperture 600mm Focal Length (f/5.6) Quintuplet Flat-Field APO Optical Design 66mm Corrected Image Circle Total Weight of 6.5kg Descriptio...

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CA$3,639.00 - CA$3,639.00
CA$3,639.00
CA$3,639.00 - CA$3,639.00
CA$3,639.00

Doublets, Triplets and Glass Types

The purpose of an apochromatic design is to bring three wavelengths to a common focus, eliminating the violet halo that achromatic refractors show on bright stars. How well it does that depends on the glass and the number of elements.

  • ED doublets: Two elements with one extra-low dispersion element. Lighter, less expensive, and excellent for imaging, with a small residual colour that is rarely visible in processed images.
  • Apochromatic triplets: Three elements giving near-complete colour correction, preferred for high-contrast visual observing and for imaging bright stars without halos. Heavier and slower to cool.
  • Petzval designs: Four-element optics with the field correction built in, so no separate flattener is needed and back-focus is fixed by the manufacturer — the simplest path to flat fields.
  • Achromatic refractors: Two-element crown and flint designs, excellent value for lunar, planetary and general visual use where some colour fringing on bright objects is acceptable.
  • Focal ratio: Fast refractors around f/5 give wide fields and short exposures; f/7 and slower give more image scale and are more forgiving of corrector spacing.
  • Matched correctors: Most refractors need a flattener or reducer designed for that specific model, spaced to its exact back-focus.

Why Choose David Astro for Refractors

A refractor is usually bought as the centre of an imaging system, so it should be specified alongside the mount and camera rather than on its own.

  • Corrector matched at the point of sale: We identify the flattener or reducer designed for your specific tube and supply the spacers to hit its back-focus exactly.
  • Focuser load assessed: We check that the stock focuser will carry your intended camera train without slip, and recommend an upgrade only when it genuinely will not.
  • Authorized dealer: Full manufacturer warranty and verified authenticity, with service handled inside Canada.
  • Ships from Canadian stock: No duties or brokerage fees for Canadian buyers, and no extra border handling for a precision optic.
  • Support after first light: Help with spacing, tilt and star shape diagnosis once the telescope is on the sky.

Refractors in Canada — Frequently Asked Questions

Doublet or triplet for imaging?
A good ED doublet is entirely sufficient for most deep-sky imaging and is lighter on the mount. A triplet shows its advantage on bright stars and in high-contrast visual use, at meaningful extra weight and cost.
Do I need a field flattener?
For imaging with anything larger than a small sensor, yes — a two-element refractor has a curved focal plane and corners will show elongated stars without one. Petzval designs have it built in.
How long does a refractor take to cool?
A small doublet is usable almost immediately. A large triplet can take 45 minutes or more to stabilize in Canadian winter conditions, and imaging before it does will show soft, bloated stars.
Is a small refractor enough for deep sky?
Yes, given integration time. A 60 to 80 mm apochromat on a good mount produces excellent wide-field images; total exposure time substitutes for aperture in imaging in a way it cannot for visual work.

Specifying a refractor?

Tell us your mount, camera and targets and we will match the tube and its corrector. Canadian stock, no surprise duties.