Celestron · Eyepiece
Celestron Omni 40mm
Reliable low-power eyepiece with honest Plossl performance at a price that leaves budget for more accessories
Performance Scores
Overview
The Celestron Omni 40mm is a low-power eyepiece designed for wide-field viewing through any standard 1.25-inch focuser. At 40mm focal length, it delivers long eye relief and a 43-degree apparent field of view, making it a practical choice for sweeping the Moon, finding large nebulae, or simply getting oriented in the night sky before switching to higher magnification. The four-element Plossl design is a well-understood, optically sound configuration that has been trusted by amateur astronomers for decades.
Fully multi-coated optics help maximize light transmission and keep images reasonably sharp and contrasty, though at this focal length and price point, some edge-of-field softness is normal and expected in a Plossl design. The aluminum barrel is threaded for 1.25-inch filters, which is genuinely useful if you plan to use a light pollution or Moon filter. Rubber eyecups fold down for eyeglass wearers, a small but practical detail.
With over 350 Amazon reviews averaging 4.6 out of 5, this eyepiece has earned consistent praise from beginners and experienced observers alike. At $52.95, it represents a straightforward, no-surprise entry into quality low-power viewing without requiring a significant investment.
At a Glance
40mm
Focal Length
Specifications
Key Features
- 40mm focal length delivers low magnification and wide context views, useful for finding objects and observing the full lunar disk
- Four-element Plossl design provides reliable optical performance with good center-field sharpness
- Fully multi-coated lenses improve light transmission and contrast compared to single-coated alternatives
- Threaded 1.25-inch barrel accepts standard filters, including Moon and light pollution filters
- Fold-down rubber eyecups make the eyepiece usable with or without eyeglasses
- Blackened lens edges and matte aluminum barrel reduce internal reflections and stray light
- Two-year US warranty with Celestron's domestic support team provides practical purchase confidence
Customer Reviews
353 reviews
Great wide field lens for Celestron 6se telescope. I use it every time I take the scope out. Feels like solid quality and image is great. Can get a large amount of Plaides and Andromeda but not all of them. Awesome for comets, clusters, other larger objects.
First off, let me start this review by saying, for an eyepiece made in China, this thing feels very well built. It's solid in your hand, actually weighs a good bit for an eyepiece. The view is incredibly clear, and the field of view is very wide. This is great for viewing large swaths of the sky at ...
A surprisingly good optic. Great finish, overall a very good low power eyepiece for the price. I use it primarily to center objects before increasing power with other eyepieces. Would definitely buy again.