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Apochromatic Refractors

An apochromatic refractor brings blue, green and red light to the same focus, so stars stay small and round with no violet halo. It is the most common telescope in deep-sky imaging, and a favourite of visual observers for its sharp, high-contrast views. We carry APO refractors from Askar, William Optics, Sky-Watcher, Explore Scientific, Tele Vue, SharpStar, SVBONY and ZWO, from 50 mm travel scopes up to the Askar 203APO.

For imaging, check two things besides the glass: whether the tube needs a separate flattener to cover your sensor, and whether its focuser can carry your camera, filter wheel and guider without sagging. We confirm both with you before you order.

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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

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

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

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

Askar 111F Flat-Field Astrograph

111mm Aperture 766mm Focal Length (f/6.9) Quadruplet Air-Spaced APO Design with ED Glass 44mm Corrected Image Circle Integrated Field Flattener Ne...

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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
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

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/7.7 Quadruplet APO

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

131mm Aperture 983mm Focal Length (f/7.5) Quadruplet Air-Spaced APO Optical Design Includes One ED Glass Element 44mm Full-Frame Image Circle Inte...

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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

140mm Aperture 980mm Focal Length (f/7) Triplet Air-Spaced APO Objective with ED Glass OTA Weight: 9.2kg | Total Weight: 10.9kg 125mm Retractable ...

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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

151mm Aperture Quadruplet APO Optics 1057mm Focal Length at f/7 Integrated Flattener for a 60mm Image Circle Includes 2 ED Glass Elements for Colo...

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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

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

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

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

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

60mm Aperture Quadruplet APO Optics 408mm Focal Length (f/6.8) 44mm Full-Frame Corrected Image Circle Integrated Field Flattener 2.4-inch Dual-Spe...

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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

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

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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

71mm Aperture Quadruplet Air-Spaced APO 490mm Focal Length at f/6.9 44mm Full-Frame Corrected Image Circle Integrated Field Flattener Design 2.4-i...

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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

80mm Aperture 560mm Focal Length (f/7) Doublet Objective with ED Glass 1.7 kg OTA Weight 2" Dual-Speed Rack & Pinion Focuser Optimized for APS...

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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/7.5 Quadruplet APO

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

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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

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$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

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

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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

72mm Aperture Quintuplet APO Lens 400mm Focal Length at f/5.6 44mm Natively Flat Image Circle 140mm Available Back Focus from M68x1 Thread 3" Rack...

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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

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

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

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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

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

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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
CA$4,753.00 - CA$4,753.00
CA$4,753.00
CA$4,753.00 - CA$4,753.00
CA$4,753.00

Askar SQA106 106mm f/4.8 Quintuplet APO

106mm Aperture f/4.8 Focal Ratio 509mm Focal Length Quintuplet Petzval APO Optical Design with 2x SD Glass 55mm Corrected Image Circle for Medium ...

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CA$4,753.00 - CA$4,753.00
CA$4,753.00
CA$4,753.00 - CA$4,753.00
CA$4,753.00

Doublets, Triplets and Flat-Field Designs

The number of lenses and the glass type change how the telescope behaves in the field.

  • ED doublets: Two elements, one in extra-low dispersion glass. Light, quick to cool and excellent for imaging. Examples: Sky-Watcher Evostar EDX, SVBONY SV503, Askar 80ED.
  • Air-spaced triplets: Three elements for near-complete colour correction. The reference for visual contrast on planets and bright stars. Examples: Askar APO series, Explore Scientific FCD100, Sky-Watcher Esprit, William Optics Fluorostar.
  • Quadruplet and quintuplet astrographs: Field correction built into the tube, so stars are sharp to the corner of a large sensor with no extra flattener. Examples: Askar FRA, SQA and PHQ, William Optics Cat series, Tele Vue NP101is and NP127is.
  • ED glass type: FPL-53 and FCD100 are the premium ED glasses. They control colour better than FPL-51, which shows most on bright stars and in high-power planetary views.
  • Focal ratio and focal length: Focal length sets the field of view, so a 400 mm f/7 frames the same sky as a 400 mm f/5. Focal ratio sets exposure time: f/5 collects signal about twice as fast as f/7. Slower designs are usually better corrected and more forgiving of focus and spacing errors.

Visual or Imaging?

  • For visual use: A 4-inch triplet on a sturdy alt-az mount is one of the most satisfying telescopes you can own. Add a quality diagonal and good eyepieces.
  • For imaging: Budget for the mount first, then the field flattener or reducer unless the tube has one built in, then the camera.

What We Check Before You Order

An APO is usually the heart of an imaging system, so we check the whole optical train with you.

  • Corrector and back-focus: We confirm which flattener or reducer is designed for your exact tube and give you the spacing to hit, including filter thickness.
  • Framing: Send us your camera and a few targets and we will show you how they fit at 250, 400 or 700 mm before you choose.
  • Focuser load: A full-frame camera, filter wheel and off-axis guider can weigh 1.5 kg. We check that the stock focuser holds it without slipping or tilting.
  • Mount margin: For imaging we keep the payload well under the mount's rating. A 130 mm triplet with rings, guide scope and camera is heavier than the tube weight suggests.

APO Refractors: Frequently Asked Questions

Is a doublet enough for astrophotography?

Yes. A good FPL-53 doublet produces excellent deep-sky images. A triplet mainly helps on very bright stars and for high-contrast visual work.

Do I need a field flattener?

With a doublet or triplet and anything bigger than a small planetary sensor, yes. Petzval and quintuplet designs such as the Askar SQA or William Optics RedCat already include one.

What size APO should I start with?

For imaging, 60 to 80 mm is the easiest place to start. It is light on the mount, forgiving of guiding and gives wide fields. For visual, 100 mm and up starts to show real planetary detail.

How long does an APO take to cool down?

A 60 to 80 mm doublet is ready in a few minutes. A 130 mm triplet can need 45 minutes or more in a Canadian winter. Set it outside early.

Planning your first or next APO?

Tell us your mount, camera and favourite targets. We will match the tube and the corrector and ship from Canada.