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Celestron 1.25" & 2" Ultima Duo Eyepiece with T Thread - 21mm # 93445

5.0 (1 Reviews) Read Reviews Write Review
Brand Celestron
Part Number 93445
Availability available

Product Info

Manufacturer Description

Get a new perspective on the Universe with Ultima Duo, Celestron's versatile new eyepieces that combine excellent optics with a built-in T-adapter for astroimaging.

Enjoy impressive views with a wide 68-degree apparent field of view. Celestron's fully multi-coated optics increase light transmission and contrast, while blackened lens edges prevent internal reflections. The result is bright, pinpoint stars on a black field. A generous 20mm of eye relief and fold-down rubber eyeguard make Ultima Duo comfortable to use without removing eyeglasses.


If you're interested in imaging through the eyepiece, Ultima Duo makes the process quick and easy. Unlike competitors' eyepieces, you won't need to spend money on expensive adapters for your camera. The industry-standard 42mm T-threads are integrated for a direct, secure connection to your DSLR or astronomical CCD camera. Just remove the rubber eyeguard to expose Ultima Duo's integral T-threads. Then attach your DSLR camera with compatible T-ring (not included) and you're ready to capture crystal clear images! Ultima Duo is ideal for imaging bright solar system objects like the rings of Saturn, craters on the Moon, and Jupiter's Great Red Spot.

Imaging the Moon and planets is even easier with Celestron's Smartphone Adapter for Ultima Duo (sold separately). Unlike "universal" adapters, the Celestron Smartphone Adapter is custom-fit for the Ultima Duo eyepiece line. With this sturdy connection, your smartphone can capture crisp, sharp images of your favorite solar system objects.

Advanced planetary imagers can attach Celestron's T-to-C Adapter (sold separately) and add a number of high-end imagers to Ultima Duo, including Celestron's Skyris and NexImage Burst cameras.


Ultima Duo's anodized aluminum body allows it to fit both 1.25" and 2" focusers, so you can use it with almost any telescope with no extra adapters required. A compact body style makes Ultima Duo an excellent choice for use with binoviewers.

The rubber grip rings provide good ergonomics so you can hold onto your eyepiece, even while wearing gloves. The aluminum barrel is threaded to accept 1.25" eyepiece filters (but not 2" filters) and has a safety recess to prevent it from slipping out of the focuser. Each Ultima Duo eyepiece includes cover caps and a protective carry pouch.

Product carries full 2 year Celestron factory limited warranty (within US/Canada only).


5.0 (Based on 1 Reviews) 100% of reviewers recommended this product.
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    1. Guest

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      User Notes:
      Review by AP beginner of Tucson.
      Oct 9, 2015

      5.0 Worth the money


      Quality Lenses,Easy to Use,Strong Construction,Accurate



      I have a non-astrograph Newtonian that I want to use for AP as well as visual. Unfortunately I am not able to focus my T3i at prime focus so I am forced to use EP projection with this scope. This EP makes that very, very easy due to the threads on the EP. These also make easy to switch back and forth between visual and AP. There are no internal reflections, color transmission is good and the contrast is good. It does everything I need it to. I like it so much that I am saving my money for the 5mm.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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      Apparent Field of View 68°
      Barrel Size 1.25" (31.7mm) and 2" (50.8mm)
      Bolt Case Included Yes - Free Agena Eyepiece Container
      Bolt Case Size Agena 65x80mm
      Coatings Fully Multi-Coated
      Height (with Eye Guard) 105mm (4.13")
      Max Width 57.5mm (2.26")
      End Caps 2
      Eye Lens Diameter 30mm (1.18")
      Eye Relief by Design 20mm
      Filter Threads Standard 1.25" Filter Thread (M28.5 x 0.6)
      Focal Length 21mm
      Lens Elements 8
      Lens Groups 5
      Rubber Eye Guard Yes
      Blackened Lens Edges Yes
      Additional Information 42mm T-Threads under eyecup
      Manufacturer Celestron
      Eyepiece Focal Length 20.1mm - 30mm
      Eyepiece Field of View 61 - 70 degrees
      Eyepiece Series Celestron Ultima Duo
      Barrel Type With safety undercut
      Eyepiece Weight 13oz (368.54g)