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Orion Telescopes
27mm Orion EF Widefield 1.25" Eyepiece
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In Stock
  • Extra flat ("EF") optical design minimizes field curvature for flatter, non-distorted images
  • Wide fields of view provide an immersive visual experience
  • Fully multi-coated, edge-blackened lenses deliver outstanding brightness and contrast
  • Twist-up eyecups block unwanted ambient light and position eye at the optimal distance from the lens
  • Safety-slotted barrels are threaded for Orion 1.25" filters

Learn more
Item #  52591

If you're ready to swap out your standard Plossl eyepieces for oculars that will take your observing game to the next level, try the Orion EF Widefield 1.25" Eyepieces. The "EF" stands for Extra Flat, which means that our EF Widefield Eyepieces are designed to minimize field curvature at the periphery, so you see an exceptionally flat, non-distorted image. All the internal lenses are fully multi-coated and edge-blackened for superior light transmission and image contrast.

As the name also implies, the fields of view of the EF Widefield Eyepieces are generously expansive to provide a comfortable, immersive view, whether you're gazing at celestial denizens or land-based subjects. Of the five different focal lengths, the 8mm and 12mm EFs have a 60-degree field of view (FOV), the 16mm and 19mm have a 65-degree FOV, and the 27mm has a 53-degree FOV.

The machined, black-anodized aluminum housings feature a rubber grip band for easy handling, even while wearing gloves, and a slotted barrel to prevent slip-outs if the locking thumbscrew on your telescope's diagonal or focuser should loosen slightly. The 1.25" barrels are also threaded to accept an array of Orion 1.25" filters. And unlike many wide-angle eyepieces on the market, each Orion EF Widefield Eyepiece sports a rubber-rimmed twist-up eyecup, which not only reduces intrusion of unwanted ambient light, but also helps position your eye at the optimal distance from the eye lens to allow visibility of the entire field of view. Eye relief (ER) varies depending on the focal length: the 8mm EF Widefield Eyepiece has 10mm ER, the 12mm has 15mm ER, the 16mm has 18mm ER, the 19mm has 18.5mm ER, and the 27mm has 23mm ER.

From the low-power 27mm to the high-power 8mm focal length, our EF Widefield 1.25" Eyepieces are sure to provide a welcome "step up" for anyone looking for a flatter, wider-field window on the universe than standard Plossl or Kellner eyepieces can deliver. And they're nicely affordable, to boot! Step up today to Orion EF Widefield 1.25" Eyepieces.


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.


Please note this product was not designed or intended by the manufacturer for use by a child 12 years of age or younger.

Product Support
Visit our product support section for instruction manuals and more
  • User level
  • Design
  • Eyepiece focal length
  • Barrel size
  • Apparent field of view
  • Eye relief
  • Coatings
    Fully multi-coated
  • Number of elements
  • Filter threads
  • Parfocal
  • Barrel security recess
  • Blackened lens edges
  • Rubber eyeguards
  • Body material
  • Case
  • Weight (oz.)
  • Additional included accessories
  • Other features
  • Warranty
    One year

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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