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Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal - 40901

SKU: ORI-40901

Orion 1.25" Twist-Tight Dielectric Mirror Diagonal Highlights


  • 90º 1.25" mirror diagonal with refined dielectric coatings featuring 99% reflectivity for highly optimal performance.
  • Twist-tight fastener holds inserted eyepieces more firmly than standard thumbscrew-equipped diagonals without scratching!
  • Tough dielectric mirror coatings offer greater reflectivity for peak brightness and contrast.
  • For enhanced performance, this diagonal has machined and anodized aluminum housing with machine-threaded glare baffles to eradicate glare.
  • Nosepiece barrel threaded to receive 1.25" filters from Orion.


Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal


Orion's 1.25" Twist-Tight Dielectric Mirror Star Diagonal puts a new spin, or "twist," on the standard thumbscrew-outfitted telescope diagonal. This ingenious diagonal contains a twist-tight fastening mechanism that firmly grips inserted 1.25" eyepeices and accessories with a mere clockwise turn of its red aluminum collar.

Contrary to diagonals equipped with thumbscrews, Orion's Twist-Tight Diagonal provides identical inward pressure to accurately center eyepieces, camera nosepieces, and other equipment located on the telescope's light path with a more rigid grip. Furthermore, because this diagonal doesn't have a thumbscrew, you don't have to be concerned about those aggravating scratches and gouges appearing on your valuable eyepieces. Plus, there's no thumbscrew to misplace in the dark! The twist-tight collar is made of knurled aluminum for a comfortable grip that's wonderfully simple to adjust, even during cold nights when the user is donning gloves.

The core of the Orion 1.25" Twist-Tight Mirror Star Diagonal is a highly reflective mirror with refined, lab-tested dielectric coatings offering a reflectivity of 99%. A reflectivity this high will enable you to achieve the most brilliant views possible with a refractor or Cassegrain telescope. Machine-threaded internal baffling within the 1.25" Twist-Tight Diagonal's durable anodized aluminum housing renders ideal contrast by eradicating annoying internal reflections and glare. And since dielectric coatings are more long-lasting than enhanced aluminum coatings, you'll experience consistent exceptional performance without deterioration well into the future.

1.25" nosepiece barrel is threaded to receive filters of identical size so you can easily switch between different eyepieces and accessories without the inconvenience of having to reattach the filter time after time. Comes with protective caps to prevent dust from accumulating on the diagonal when not in use.

Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal Specifications


  • Design: Kellner
  • Barrel Size: 1.25"
  • Coatings: Dielectric
  • Optical Quality: DIffraction limited
  • Filter Threads: Yes
  • Body Material: Aluminum
  • Compression Ring: Yes
  • Weight: 8 oz.
  • Warranty: 1 year