TS Optics Premium 5.5mm Flat Field 60° 1.25″ Eyepiece
Sharp and Comfortable Viewing
The TS Optics Premium Flat Field eyepiece is a popular choice among astronomers who want a combination of comfortable observation and outstanding optical quality. It delivers a wide 60° field of view with excellent correction all the way to the edge of the image. The six-element design in four groups ensures high light transmission, making full use of your telescope's light-gathering power. The rubber eyecup folds down for eyeglass wearers and provides a comfortable viewing position during long observing sessions.
Optical Design
This eyepiece is specifically designed to produce a flat and sharp image field even with fast optical systems that have a low focal ratio. Six lenses in four groups minimise aberrations and image distortion. The inner barrel is fully blackened to suppress stray light reflections and maintain high contrast. An eye relief of 16mm means you do not need to press your eye close to the eyepiece - a feature you will appreciate during extended sessions at the telescope.
Build and Compatibility
The standard 1.25″ barrel fits the vast majority of telescopes available today. The eyepiece does not include a safety groove, but its compact dimensions - 68mm in length and just 91g in weight - make it an excellent choice for binocular viewing setups where low weight is essential. The field stop diameter of 6.4mm matches the 5.5mm focal length and produces a cleanly defined field of view without distracting light effects at the edges.
What Can You Observe
Deep-Sky Objects
High light transmission lets you make full use of your telescope's aperture. Faint objects such as nebulae and galaxies are rendered with good brightness and detail.
Moon and Planets
The fully blackened interior keeps contrast high and brings out fine surface detail on the Moon and planets.
Double Stars
Double star observation is where this eyepiece performs particularly well. Even a relatively faint companion star is clearly distinguishable, provided your telescope has sufficient resolving power.
Binocular Viewing and Eyepiece Projection
The slim barrel profile makes this eyepiece easy to pair in a binocular viewing assembly. The narrow design also fits standard eyepiece projection adapters, so you can use it for astrophotography by projection.
Who Is This Eyepiece For
This is a versatile eyepiece that suits both beginners taking their first steps in astronomy and experienced observers who need a reliable, high-quality eyepiece for regular telescope use.
Technical Specifications
| Parameter |
Value |
| Focal length |
5.5mm |
| Field of view |
60° |
| Barrel diameter |
1.25″ |
| Optical design |
6 elements in 4 groups |
| Eye relief |
16mm |
| Field stop diameter |
6.4mm |
| Length |
68mm |
| Weight |
91g |
| Safety groove |
No |
| Eyecup |
Fold-down rubber, suitable for eyeglass wearers |
