Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal
Item #40901
5.0 / 5.0
Free Standard Shipping
$119.99 $89.99
This high-end diagonal features 99% reflectivity and a twist-tight clamping mechanism to securely grasp inserted 1.25" accessories with a simple clockwise twist of its red aluminum collar.
This item is on backorder and expected by 11/25/2023.
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  • More Info
    • 1.25", 90-degree mirror diagonal features sophisticated dielectric coatings with highly efficient 99% reflectivity for peak performance
    • Twist-tight clamping mechanism grips inserted eyepieces more securely than typical thumbscrew-equipped diagonals - without scratching!
    • Durable dielectric mirror coatings provide higher reflectivity for maximum brightness and contrast
    • Machined and anodized aluminum housing features machine-threaded glare baffles to eliminate glare for great performance
    • Nosepiece barrel threaded to accept 1.25" Orion filters

    The Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal gives the typical thumbscrew-equipped telescope diagonal a new twist -- literally! This innovative diagonal features a twist-tight clamping mechanism that securely grasps inserted 1.25" eyepieces and accessories with a simple clockwise twist of its red aluminum collar.

    Unlike thumbscrew-equipped diagonals, the Orion Twist-Tight diagonal delivers equal inward pressure to precisely center eyepieces, camera nosepieces, and other equipment along the light path of the telescope with a more robust grip. What's more, since this diagonal doesn't use a thumbscrew, you don't have to worry about annoying scratches or gouges appearing on your treasured eyepieces, and there's no thumbscrew to lose in the dark! The easy-grip, knurled aluminum twist-tight collar is delightfully easy to adjust, even while wearing gloves during cold nights.

    The Orion 1.25" Dielectric Twist-Tight Mirror Star Diagonal is built around a highly reflective mirror with sophisticated, lab-tested dielectric coatings providing 99% reflectivity. With such high reflectivity, this diagonal will help you obtain the brightest views possible through a refractor or Cassegrain telescope. The 1.25" Twist-Tight Diagonal's rugged anodized aluminum housing features machine-threaded internal baffles to ensure optimal contrast and also eliminate pesky internal reflections and glare. What's more, since dielectric coatings are more durable than enhanced aluminum coatings, you'll enjoy year after year of exceptional performance without degradation. 

    The diagonal's 1.25" nosepiece barrel is conveniently threaded to accept like-sized filters so you can easily swap between different telescope eyepieces and other accessories without the hassle of re-attaching the filter each time. Protective caps are included to keep the diagonal free of dust when not in use.

    Please note: diagonals are not recommended for use with Newtonian reflector telescopes.


    Limited Warranty against defects in materials or workmanship for one year from date of purchase. This warranty is for the benefit of the original retail purchaser only. For complete warranty details contact us at 800-447-1001.

  • Specs
    • User level:
    • Design:
    • Barrel size:
    • Coatings:
    • Optical quality:
      Diffraction limited
    • Filter threads:
    • Body material:
    • Compression ring:
    • 2"-1.25" adapter:
      Sold separately
    • Weight (oz.):
    • Additional included accessories:
    • Other features:
    • Warranty:
      One year
  • Important Shipping Information

    Orders received by 1pm Eastern Standard Time for in-stock items ship the same business day. Order received after noon will ship the next business day. When an item is not in-stock we will ship it as soon as it becomes available. Typically in-stock items will ship first and backordered items will follow as soon as they are available. You have the option in check out to request that your order ship complete, if you'd prefer.

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