Explore Scientific ED Air-Spaced Triplet APO Refracting Telescopes

Apochromatic (APO) lenses are designed to bring three wavelengths of light (red, green, and blue) into focus in the same plane. In contrast, achromatic lenses are corrected to bring two wavelengths into focus in the same plane.

Achromatic Doublet Lens Diagram. Image source: Wikipedia

The classic achromatic doublet made from optical crown and flint glasses bring two colors of light to a common focus. This diagram shows the image forming lens in the front and the correcting lens in the back. 

Apochromat optics were first developed by Peter Dolland in 1763. His air-spaced triplet design ushered forth many optical improvements but lacked the use of ED glass that we see in most apochromatic optical designs today. ED glass enhances apochromatic lens design by producing extra-low dispersion of the wavelengths of light passing through it thereby giving an even better apochromatic performance.  For more specifications and information on the different types of glass used in Explore Scientific apochromatic triplets, please click here.

Example of Apochromatic Optical Performance. Image source: Wikipedia

Explore Scientific true apochromatic telescopes utilize three air-spaced elements with the ED element in the middle to bring the light of three different frequencies to a common focus, thus mitigating the effects of chromatic aberration.

  • Explore Scientific ED80 Essential Series Air-Spaced Triplet Refractor - ES-ED0806-01
    Explore Scientific ED80 Essential Series Air-Spaced Triplet Refractor - ES-ED0806-01
    Save 12%
    Original Price $ 849.99
    Current Price $ 749.99

    Explore Scientific ED80 Essential Series Air-Spaced Triplet Refractor - ES-ED0806-01

    Explore Scientific

    Description The ED80 Essential Series Air-Spaced Triplet Refractor is a true apochromatic telescope that reveals celestial wonders like the desola...

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    Original Price $ 849.99
    Current Price $ 749.99
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  • Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope - ES-ED10207-01
    Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope - ES-ED10207-01
    $ 1,199.99

    Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope - ES-ED10207-01

    Explore Scientific

    Temporarily Out of Stock, But More are On The Way! The Explore Scientific ED102 Essential Series is Available for Back-Order Purchase or Layaway D...

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    $ 1,199.99
  • Explore Scientific ED127 Essential Series Air-Spaced Triplet Refractor - ES-ED127075–03
    Explore Scientific ED127 Essential Series Air-Spaced Triplet Refractor - ES-ED127075–03
    $ 1,899.99

    Explore Scientific ED127 Essential Series Air-Spaced Triplet Refractor - ES-ED127075–03

    Explore Scientific

    Description Temporarily Out of Stock, But More are On The Way! Estimated Restock Date is Early July. The Explore Scientific ED127 Essential Series...

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    $ 1,899.99
  • Explore Scientific ED152 Air-Spaced Triplet in Carbon Fiber - TED15208CF-HEXDD3
    Explore Scientific ED152 Air-Spaced Triplet in Carbon Fiber - TED15208CF-HEXDD3
    Save 27%
    Original Price $ 5,499.99
    Current Price $ 3,999.99

    Explore Scientific ED152 Air-Spaced Triplet in Carbon Fiber - TED15208CF-HEXDD3

    Explore Scientific

    Description Observing with the ED152 Air-Spaced Triplet FCD1 Series Apochromatic Refractor in Carbon Fiber with genuine HOYA FCD1 ED Glass: Seriou...

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    Original Price $ 5,499.99
    Current Price $ 3,999.99
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  • Explore Scientific ED80-FCD100 Series Air-Spaced Triplet Refractor - FCD100-0806-01
    Explore Scientific ED80-FCD100 Series Air-Spaced Triplet Refractor - FCD100-0806-01
    $ 1,199.99

    Explore Scientific ED80-FCD100 Series Air-Spaced Triplet Refractor - FCD100-0806-01

    Explore Scientific

    Description Temporarily Out of Stock, But More are On The Way! Estimated Restock Date is Early July. The Explore Scientific ED80 FCD100 Series is ...

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    $ 1,199.99
  • Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Refractor Telescope - FCD100-10207-01
    Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Refractor Telescope - FCD100-10207-01
    $ 1,899.99

    Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Refractor Telescope - FCD100-10207-01

    Explore Scientific

    Description Reveal celestial wonders like the desolate beauty of the lunar terrain, the serene structure of Saturn’s rings or the brightest deep s...

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    $ 1,899.99
  • Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Telescope in Carbon Fiber - FCD100–10207-CF
    Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Telescope in Carbon Fiber - FCD100–10207-CF
    $ 2,199.99

    Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Telescope in Carbon Fiber - FCD100–10207-CF

    Explore Scientific

    Description The Explore Scientific ED102-FCD100 Series Air-Spaced Triplet Telescope in Carbon Fiber, has the advantages for astrophotographers and...

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    $ 2,199.99
  • FCD100 Series 127mm f/7.5 Aluminum Air-Spaced Triplet ED APO Refractor with 2.5" HEX Focuser
    FCD100 Series 127mm f/7.5 Aluminum Air-Spaced Triplet ED APO Refractor with 2.5" HEX Focuser
    Save 17%
    Original Price $ 2,399.99
    Current Price $ 1,999.99

    FCD100 Series 127mm f/7.5 Aluminum Air-Spaced Triplet ED APO Refractor with 2.5" HEX Focuser

    Explore Scientific

    Description Reveal celestial wonders like the desolate beauty of the lunar terrain, the serene structure of Saturn’s rings or the brightest deep s...

    View full details
    Original Price $ 2,399.99
    Current Price $ 1,999.99
    Save 17%
  • Explore Scientific FCD100 Series 127mm f/7.5 Carbon Fiber Triplet ED APO Refractor Telescope with 2.5" HEX Focuser
    Explore Scientific FCD100 Series 127mm f/7.5 Carbon Fiber Triplet ED APO Refractor Telescope with 2.5" HEX Focuser
    Save 13%
    Original Price $ 2,999.99
    Current Price $ 2,599.99

    Explore Scientific FCD100 Series 127mm f/7.5 Carbon Fiber Triplet ED APO Refractor Telescope with 2.5" HEX Focuser

    Explore Scientific

    Description Reveal celestial wonders like the desolate beauty of the lunar terrain, the serene structure of Saturn’s rings or the brightest deep s...

    View full details
    Original Price $ 2,999.99
    Current Price $ 2,599.99
    Save 13%
  • ED115 FPL53 115mm f/5.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser
    ED115 FPL53 115mm f/5.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser
    $ 3,499.99

    ED115 FPL53 115mm f/5.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser

    Explore Scientific

    Description Reveal celestial wonders like the desolate beauty of the lunar terrain, the serene structure of Saturn’s rings or the brightest deep s...

    View full details
    $ 3,499.99
  • ED140 FPL53 140mm f/6.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser
    ED140 FPL53 140mm f/6.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser
    $ 5,999.99

    ED140 FPL53 140mm f/6.5 Air-Spaced Triplet ED APO Refractor in Carbon Fiber with 3" HEX Focuser

    Explore Scientific

    Description Reveal celestial wonders like the desolate beauty of the lunar terrain, the serene structure of Saturn’s rings or the brightest deep s...

    View full details
    $ 5,999.99
  • Explore Scientific ED165-FPL53 Air-Spaced Triplet Refractor - FPL53–165CF-01
    Explore Scientific ED165-FPL53 Air-Spaced Triplet Refractor - FPL53–165CF-01
    $ 11,999.99

    Explore Scientific ED165-FPL53 Air-Spaced Triplet Refractor - FPL53–165CF-01

    Explore Scientific

    Description Explore Scientific's largest refractor telescope incorporates our true three-element apochromat design the ED165-FPL53 with an apertur...

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    $ 11,999.99