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William Optics 1.25" & 2" 101° XWA Extreme Wide Angle Eyepiece - 9mm

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Brand William Optics
Part Number E-XWA09

Product Info

Manufacturer Description

See what William Paolini, noted amateur astronomer and author of Choosing and Using Astronomical Eyepieces, had to say about this eyepiece on CloudyNights.com.

  • “This is a really sweet eyepiece, has a nice eyecup function, the dual skirt is very elegant so that with it on it looks like a native 2" EP and with it off it looks like a native 1.25" EP, and it is surprisingly killer on planets and sharp to the edge. Since this is a good higher power eyepiece for the little 60mm [f/16.7 refractor], I decided to use it. The WO 9mm 101 showed the entire disk with room to spare at 111x and was completely mesmerizing! The BIG 101 degree view from this eyepiece made me feel like the scope was similarly a BIG performer, taking away any notion that is was anything but big performer.”

  • "I put this eyepiece in my f/8 [telescopes] as well and again sharp to edge. I've not tried it side by side with the Explore Scientific 9mm, but from memory this one seemed better edge corrected. Again though, the build is just so thoughtful as dual skirted eyepieces are usually cludgy looking...this one is quite elegant...only one of the 100's out there that I really liked aesthetically and functionally (the build)."

New from William Optics - Offered at a special introductory price (while supplies last)!

  • William Optics 9mm 101-deg Extreme Wide Angle (XWA) eyepiece
  • Dual 1.25" and 2" barrel format
  • Comfortable 15mm eye relief
  • Twist-up eyecup
  • Fully multi-coated optics (9 elements in 6 groups) with blackened lens edges
  • Made in Taiwan from Taiwanese, Chinese, and Japanese components
  • 1.25" eyepiece with 2" sleeve. 2" barrel uses a unique / innovative male 1.25" filter thread on the inside to connect to the female filter thread on the 1.25" barrel.


  • Weight: 
    • 1.25" eyepiece: 1lb-4.6oz
    • 2" sleeve: 2.3oz
    • 2" eyepiece: 1lb-6.9oz
  • Height:
    • 1.25" eyepiece (with eyeguard recessed): 146.8mm (5.78")
    • 2" eyepiece (with eyeguard recessed): 150.2mm (5.91")
    • Eyeguard can extend by: 7.5mm (0.3")
  • Maximum width (excluding end caps): 65mm (2.56")


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Apparent Field of View 101°
Barrel Size 1.25" (31.7mm) and 2" (50.8mm)
Bolt Case Included Yes - Free Agena Eyepiece Container
Bolt Case Size Agena 85x120mm
Coatings Fully Multi-Coated
Height (with Eye Guard) See item description
Max Width 65mm
End Caps 3
Eye Lens Diameter 27.7mm
Eye Relief by Design 15mm
Filter Threads Standard 1.25" (M28.5 x 0.6) and 2" (M48 x 0.75) Filter Thread
Focal Length 9mm
Lens Elements 9
Lens Groups 6
Rubber Eye Guard Twist-up Eyecup
Eyepiece Weight 22.90oz (649.20g)
Blackened Lens Edges Yes
Manufacturer William Optics
Eyepiece Focal Length 5.1mm - 10mm
Eyepiece Field of View Over 80 degrees
Eyepiece Series William Optics XWA
Barrel Type With safety undercut