GSO Plössl 25mm eyepiece 50° 1.25″
Looking for a reliable eyepiece that handles everyday astronomical observation without breaking the bank? The GSO Plössl 25mm is exactly what you need. It features the classic four-element Plössl design that has maintained a strong reputation in the astronomy community for decades - and for good reason. It offers a balanced combination of field of view, aberration correction, and affordable price, making it an excellent choice for both beginner observers and experienced astronomers looking for a backup or wide-field eyepiece.
Four-element Plössl optical design
The eyepiece is built around two symmetrically arranged achromatic doublets. This configuration delivers very good correction of both spherical aberration and coma across the entire image field, resulting in a sharp and high-contrast image all the way to the edges of the field of view.
The 50° apparent field of view is typical for Plössl eyepieces and fully sufficient for many purposes. At a focal length of 25mm, you get a comfortable wide-field view - ideal for locating deep-sky objects, open star clusters, or for initial orientation on the night sky.
Fully coated optics for better contrast
All optical surfaces feature FC (Fully Coated) anti-reflection treatment, which significantly reduces unwanted reflections and light scatter. The result is improved light transmission, better contrast, and sharper rendering of fine details - particularly noticeable when observing faint objects or working with faster telescopes.
Sturdy build and wide compatibility
The eyepiece body is solidly constructed. The standard 1.25″ (31.75mm) barrel ensures compatibility with the vast majority of telescopes available on the market. The rubber fold-down eyecup allows comfortable viewing both with and without glasses - simply fold it down and your eye naturally finds the optimal distance from the lens.
A versatile wide-field instrument
The 25mm focal length makes this eyepiece a universal wide-field tool. When paired with telescopes of moderate focal ratios (f/5 to f/8), it delivers very pleasing results with minimal vignetting or edge distortion. It is a classic choice for a first look at Messier objects, wide-field constellation sweeping, or casual lunar observation with comfortable magnification.
Specifications
| Parameter |
Value |
| Optical design |
Plössl (4 elements in 2 groups) |
| Focal length |
25mm |
| Apparent field of view |
50° |
| Barrel diameter |
1.25″ (31.75mm) |
| Optical coatings |
FC - Fully Coated |
| Eyecup |
Rubber fold-down |
Who is this eyepiece for?
- Beginner astronomers equipping their first telescope
- Experienced observers looking for a reliable wide-field or finder eyepiece
- Anyone who wants a proven Plössl eyepiece at an accessible price
- Visual observers focused on deep-sky objects, star clusters, and the Moon
Summary
The GSO Plössl 25mm eyepiece is a time-tested, technically mature choice that deserves a place in any eyepiece collection. Whether you are equipping your first telescope or adding a wide-field eyepiece to a more advanced setup, it will perform reliably without compromising on fundamental optical quality.
