Focal Length: 5mm (0.20″)
Apparent Field of View (deg): 68°
Eye Relief: 20mm (0.79″)
Barrel Size: 1.25″ (32 mm), but can fit 2″ focusers
Adapter Threads: 42mm T-threads under cap
Lens Design: 8 elements in 5 groups
Optical Coatings: Fully Multi-Coated
The Celestron Ultima Duo series are versatile eyepieces that combines excellent optics with a built-in T-adapter for astrophotography. 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.
The beauty of this versatile eyepiece is that you can use it as a camera lens with your telescope! The industry-standard 42 mm T-threads are integrated for a direct, secure connection to the T-Ring (sold separately) of your DSLR or astronomical CCD camera. Just remove the rubber eye-guard to expose Ultima Duo’s integral T-threads. Then attach your DSLR camera (with compatible T-ring) and you’re ready to for some astrophotography!
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.
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 even 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 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 duo purpose eyepiece is currently available in 3 different focal lengths: 5, 17, and 21mm.
2-year Accessories Warranty included