Explore Scientific 92° LER Series 2'' Eyepieces
Explore Scientific 92° LER Series 2'' EyepiecesExplore Scientific 92° LER Series 2'' EyepiecesExplore Scientific 92° LER Series 2'' Eyepieces

Explore Scientific 92° LER Series 2" Eyepieces

  (2 Reviews)
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About this product

Model:  es_92_17mm
Part Number:  0219917

Designed to balance the modern demands of field sharpness over a wide apparent field, with long eye relief, which is of particular benefit to those who wear glasses while observing. 

The 8 lens (6 groups) optical design yields superbly corrected views and the long eye relief and wide ocular diameter combine to deliver a fantastic user experience.  

The 12mm focal length will be a good fit for many different telescope designs and focal ratios. Those who have lower focal ratio instruments, such as shorter ED and Apo refractors, will adore the widefield deep sky views this eyepiece delivers.  Whilst owners of 8, 9.25 and even 10-inch (on nights of good seeing) SCT or RC telescopes, who are looking for higher power planetary and lunar magnifications will love what this eyepiece does for their particular instruments.

The 17mm focal length will be a good fit for many different telescope designs and focal ratios. Those who have lower focal ratio instruments will adore the widefield deep sky views this eyepiece delivers.  Whilst owners of 10, 12 and 14-inch SCT or RC telescopes, who are looking for higher power planetary and lunar magnifications will love what this eyepiece does for their particular instruments.

Explore Scientific's EMD coatings provide exceptional contrast and combat internal reflections extremely efficiently.  Internal baffles and blackened internal fittings complement the EMD coatings.

Explore Scientific 92° Argon  LE eyepieces are Argon purged and completely waterproof - so is impervious to dirt, moisture and fungal ingress.

Threaded to accept 2" filters. 


  • Wide-angle 92 degree Apparent Field Of View
  • Premium grade optical glass
  • All surfaces fully multicoated for maximum light transmission
  • Internal baffles and blackened lens edges and internal metal surfaces to maximise contrast and reduce ghosting
  • Long eye-relief (good for eyeglass wearers)
  • Foldable rubber eyecups
  • Tapered 2" barrel for extra security

Eyepiece Field of View Simulator


Model 12mm 17mm  
Product Code 0219912 0219917
Eye Relief 19.9mm 22mm
Field Diaphragm (virtual) 19.6mm 27.4mm
Barrel Size 2” / 50.8mm 2” / 50.8mm
Barrel Length 33mm 39mm
Lenses 8 8
Lens Groups 6 6
Height (From End of Barrel) 154mm 148mm
Width 70mm 72mm
Eyecups Foldable rubber eyecups Foldable rubber eyecups
Weight 1100g 1100g

Customer reviews

Average Rating (2 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Very crisp immersive wide-field 2 inch eyepiece.
10 January 2020  | 

I have the 12mm 92 degree 2 inch ES eyepiece. It works very nicely on my 5 inch Refractor, giving me a True field of just over 1 degree and an exit pupil of 1.5mm.
It compares very well with my 17mm 2 inch TV Nagler for crisp immersive views. I did consider a similar focal length Nagler but the eye relief was too short to wear glasses with. I wanted around 80x at a minimum true field of 1 degree so I took the punt - not so much of a punt though as I already have the ES 24mm 82 degree eyepiece which is very good.
It didn’t disappoint. With an eye relief of 19.9mm, I could get the full field easily wearing my glasses.
The hot young blue stars in M45 at 2 degree width showed beautifully though outside the 1.13 degree eyepiece true field of view.
M42 was very nice also- the Trapezium was beautifully resolved and I was able to get glimpses of the faint E and F stars due good seeing and transparency. The nebulosity was clear and contrasted. I personally, wouldn’t want to go any higher in magnification for M42 or narrower than the 1 degree true field as the view was framed beautifully and was stunning.
It’s a big eyepiece and weighty at 1100g ( though not as heavy as the 1450g 17mm Nagler) so consider scope balance once the focuser is drawn out - It was fine for my tube which is 975mm focal length- I did have to adjust the dovetail to get the balance, though.
I would very much recommend the 12mm 92 deg ES eyepiece on its own but particularly for those who wear glasses and want very near Nagler performance but for whom the eye relief of the Nagler at around this focal length is too short.
I would say you need at least 17mm minimum with eyepieces if you wear glasses. The 17mm Nagler gives 17mm eye relief but at shorter eye piece focal lengths, the range offers insufficient eye relief for glasses wearers- which is where the 82 and 92 degree ES eye pieces fill the gap nicely.

Rating (max 5):  
Game changer for glasses wearers
20 November 2018  | 

Since the introduction of Tele Vue 80°+ (& imitations) field of view eyepieces, those who have to or prefer to wear eyeglasses have missed out on being able to use eyepieces with very wide apparent fields of view, due to too-short eye relief, &/or too critical eye positioning.

These Explore Scientific 92° eyepieces put that right, at least for the 2 focal lengths made so far. They have eye relief and comfort exceeding any other make or design so far. Their 92° apparent field of view is 10° wider than Naglers, and 8° short of Ethos. But their biggest and best feature is the eye comfort they give, with sufficiently long eye relief, and easy to hold exit pupil. 30 years I have waited for suchlike.

I started by buying the 12.5mm for viewing globular clusters, smaller nebulae and portions of larger starfields. No astigmatism, or edge of field issues, a truly immersive "spacewalk" viewing experience. Not long after I bought the 17.5mm for wider views, Andromeda Galaxy M31, and M42 Orion Nebula, where the larger exit pupil benefits use of narrowband filters like OIII.

If you wear glasses, I recommend these eyepieces for their comfort, ease of use, and for anyone, their superb performance.


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