GSO Elliptical Secondary Mirror - 120mm (Quartz Glass)

Our Price: $230.00
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Our Product ID: PATM-GS-E120Q
Manufacturer SKU: AD077
Item Can Ship: Worldwide
GSO Elliptical Secondary Mirror - 120mm (Quartz Glass)

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Product Details

For years, GSO has made dobsonian telescopes sold under various labels. Users of these scopes know the excellent quality of the optics included, and they have a well-deserved reputation for being the finest mirrors in their price range. We are now pleased to offer virtually the entire line of GSO's Newtonian optics in the US market.

This precisely figured secondary flat is made from optical grade quartz glass for enhanced thermal stability. Quartz is superior in thermal characteristics to BK7 glass or soda lime float glass. The mirror is coated with enhanced aluminum to a nominal reflectivity of 92-95% and is overcoated with a protective layer of SiO2 (quartz) for durability.

GSO uses high-volume, state-of-the-art, high quality manufacturing and test lines. GSO guarantees diffraction limited performance, but their secondary mirrors typically have a mirror surface quality of 1/12 wave RMS at least, and often better. This very smooth mirror surface results in excellent optical performance with practically no light scatter.


  • Manufacturer part #: AD077
  • Minor axis diameter: 120mm
  • Approx. major axis diameter: 169.7mm
  • Approx. thickness: Xmm
  • Weight: Xoz (Xg)
  • Glass material: Quartz