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Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"

Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"
Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"
-39 %
Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"
Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"
Celestron Ultima Duo 17mm Eyepiece - 2" / 1.25"
Ex Tax: £70.75
  • Stock: 1
  • Model: 93444
  • Shipping Weight: 0.70kg
  • SKU: 93444
  • UPC: 050234934442
  • MPN: 93444
  • Location: F6B1

Celestron Ultima Duo 17mm Eyepiece - fits 2" and 1.25" focusers

Read Astronomy Now Magazine's Online Review of the Ultima Duo Series Here.

Note from 365Astronomy

Some customers reported on forums that this series of eyepieces might be a rebranded copy of Baader Hyperion eyepieces. We have no confirmation of this from Celestron, but the eyepieces certainly look very similar, plus it seems that the 1.25" nosepiece can be unscrewed, so we won't be surprised if the famous modular eyepiece design of Hyperion eyepieces was also kept intact in these eyepieces, which means that by adding various extensions we can achieve various focal lengths, or by simply unscrewing the 1.25" nosepiece, we end up with a long focal length, widefield 2" eyepiece. One thing was certainly changed and redesigned in these eyepieces, instead of a M43 thread and then the need to use an adapter to convert it to a T-thread (M42x0.75), these eyepieces come with a T-thread without a need for any adapters. At the moment we would also include a T-thread to C-mount adapter, so you would be able to attach a Celestron Skyris or similar CCD or CMOS camera. To attach a dSLR camera you would still need a camera specific T-ring and some additional T-threaded extension...see the description of Hyperion eyepieces for details.

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.

Perfect for Imaging

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 42 mm 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) 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 our Smartphone Adapter for Ultima Duo. 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 and add a number of high-end imagers to Ultima Duo, including our Skyris and NexImage Burst cameras.

Smart Design for Use in the Field

Ultima Duo’s anodized aluminum body allows it to fit both 1.25 inch and 2 inch 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 inch eyepiece 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.

This eyepiece is available in 6 focal lengths:

5 mm
8 mm
10 mm
13 mm
17 mm
21 mm


  • High performance photo-visual eyepieces quickly switch between observing and imaging
  • Fully multi-coated optics with 8 elements in 5 groups for the best correction of chromatic aberration and field curvature
  • Extra wide 68-degree apparent field of view
  • Full 20 mm of eye relief
  • Integral 42 mm T-adapter threads and threaded barrel for filters


  • Height of eyepieces: 95 mm to 120 mm
  • Width of eyepieces: 60 mm
  • Adapter threads: 42 mm T-Threads under cup
  • Lens design: 8 element in 5 groups
  • Optical coatings: Fully multi-coated
  • Apparent field of view: 68 degrees
  • Filter threads: Fits Celestron 1.25" filters


Focal Ratio f/
Focal Length (mm)17
Eye Relief (mm)20
Angular Field of View (degrees)68
General Information
Weight in Kg0.7

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