Going Wider: Five 100-Degree Eyepieces Compared

All photos by Alan Dyer.

Note: For definitions of basic eyepiece characteristics mentioned below, see Ed Ting’s A Beginner’s Guide to Telescope Eyepieces.

Eyepieces with 100° apparent fields of view provide the widest actual fields possible at any given focal length (with the exception of the few 110° and 120° models on offer). The field is so wide it can be hard to see the edge of the field. But then again, that’s more or less the point — the eyepiece gets out of the way so you no longer have the sense you are looking through a round porthole or window.

I tested several eyepieces advertised as having 100° fields, all with focal lengths from 13mm to 15mm, a good “sweet spot” for any eyepiece on most telescopes, and encompassing the focal length of the original 13mm Nagler and Ethos models from Tele Vue. Make no mistake, these are large and heavy eyepieces, with some requiring 2-inch focusers. I tested these on f/6 apo refractors and f/5 to f/6 Newtonian reflectors, concentrating on comparing on-axis and off-axis sharpness. I present them in order of increasing price.

For a lighter, lower-cost alternative, and for 1.25-inch focusers, you might wish to consider an 82° eyepiece.

My conclusion upon testing this 100° group was that performance was more or less commensurate with price. The Meade and Omegon represent great values. Though more costly, the Stellarvue Optimus also stood out for price vs. performance in a full 100° eyepiece. The Explore Scientific 100° came very close to matching the top-class Tele Vue Ethos, but at a lower, though still premium price. But the original Ethos remains unmatched for optics.

 

Omegon Panorama2 15mm

MSRP $270

Pros:    Very good optical performance and construction; long eye relief.

Cons:   Less than 100° apparent field.

Omegon in Germany offers many unique products such as their Panorama2 eyepieces. While low cost for a 100° eyepiece, consider import fees if ordering from Europe. I ordered mine from Omegon and overseas delivery was prompt. Performance is excellent, with stars sharp across all but the outer 10 percent of the field. Eye relief is a very long 20mm. However, the Omegon and Meade both have apparent fields closer to 90° as I measured it. While still impressive, they aren’t as wide as the others. The Omegon’s weight is 600 grams, at the lower end of the range for eyepieces in this group.

Bottom Line: A good ultra-wide eyepiece for the money.

 

Meade MWA 15mm

MSRP $270

Pros:    Very good optical performance and construction; long eye relief.

Cons:   Less than 100° field.

Like twins separated at birth, Meade’s MWA (Mega Wide Angle) looks nearly identical to the Omegon Panorama2. Optical performance is also identical and excellent for the money. The knurled grip rings and construction of both are superb. Either model represents an excellent value in a mega-wide eyepiece. Note the Meade’s middle-weight 638 gram mass and that both the Meade and Omegon are just for 2-inch focusers, requiring more costly 2-inch filters.

Bottom Line:   Another fine ultra-wide eyepiece for the money.

 

Stellarvue Optimus 13.5mm

MSRP $350

Pros:    Lightest 100° with good eye relief.

Cons:   Slightly soft off-axis performance.

At 564 grams even with its 2-inch adapter tube, Stellarvue’s Optimus is the lightest of the 100° set, a consideration for balancing smaller telescopes. Like the Ethos, it can be used as either a 2-inch or 1.25-inch eyepiece. Stars begin to distort in the outer 25 percent of the field, so worse than the Explore Scientific and Tele Vue Ethos, but still very good, especially for the price. Eye relief is a comfortable 13mm and there’s no annoying kidney-bean shadowing of the exit pupil, true of the others in this group.

Bottom Line:   Very good performance vs. price.

 

Explore Scientific 100° Series 14mm

MSRP $550

Pros:     Superb star images.

Cons:    Heavy and 2-inch only; shorter eye relief.

The Explore 100° comes a very close second to Tele Vue in sharpness, with stars sharp across 90 percent of the field and still well contained at the edge. At a measured 13mm, eye relief seems a little tight, and 1.5mm less than specified, due to the eye lens being more deeply recessed than in the others. But viewing with glasses on is still possible. The main drawback is the massive 833 gram weight, by far the highest of the 100s. And it is just for 2-inch focusers and so requires 2-inch filters. But it is an excellent eyepiece, for $80 less than the Tele Vue Ethos. It comes with a vinyl storage bag and the eyepiece is fully waterproof — it can even be submerged for cleaning!

Bottom Line:  Near-Ethos image quality for less money.

 

Tele Vue Ethos 13mm

MSRP $630

Pros:     Best eye relief and off-axis star images.

Cons:    Highest cost.

This is the original 100° eyepiece and is still the standard of excellence. Eye relief is 15mm, a little longer than the Explore and Stellarvue competitors. And stars are tack sharp across 95 percent of the field, flaring only slightly at the very edge. It performs well on faster telescopes, a key characteristic of Nagler and Ethos eyepieces. Despite its size and dual barrel, its mass is only 586 grams, less than some of the competitors. But the price is the highest. Though if you want the best, this is it.

Bottom Line:   The standard of performance for 100° eyepieces.

 

Read Alan Dyer’s comparison of nine 82-degree eyepieces

 

About Alan Dyer

Alan Dyer is an astrophotographer and astronomy author based in Alberta, Canada. His website at www.amazingsky.com has galleries of his images, plus links to his product review blog posts, video tutorials, and ebooks on astrophotography.

Related posts