Product Overview
Ursa Major 7-21mm 1.25" FMC Zoom Eyepiece
An excellent value Zoom eyepiece and a useful upgrade to regular eyepieces included with many beginner telescopes.
Zoom eyepieces enable you to change the level of magnification simply by twisting the sleeve, so there is no need to swap between multiple eyepieces.
The eyepiece focal lengths are parfocal across the zoom range, so little or no focus adjustment is required when changing magnifications.
Long 16.3-18mm eye-relief, so suitable for use with eyeglasses.
A fold-up eye-cup helps you find the correct eye position and protects against stray light.
Other features include an anodised aluminium body with a tactile grip and a recessed 1.25" nosepiece that is threaded for 1.25" astronomy filters.
- 7-21mm Zoom Eyepiece
- 6 element / 4 group design
- 40-57º Field of View
- 16.3mm-18mm Eye Relief
- Fully multicoated optics
- Blackened lens edges
- CNC machined aluminium body
- Tactile rubber grip
- Recessed nosepiece to prevent slippage
- Fold-up rubber eye-cups
- 1.25" nosepiece
- Threaded for 1.25" astronomy filters
- Weight ~133g
- Height 93 mm
Eyepiece Field of View Simulator
Specifications
| Focal Length | 7-21mm |
| Nosepiece Size | 1.25" / 31.7mm |
| Apparent Field of View | 40-57º |
| Eye Relief | 16.3mm-18mm |
| Optics | Fully Multi-Coated, Blackened Lens Edges |
| Lenses | 6 Elements in 4 Groups |
| Height | Approximately 93mm |
| Weight | 133g |
| Filters | Accepts filters with 1.25" Threads (M28.5x0.6) |
| Accessories | Two Lens Caps |
