Celestron SkyMaster Gemini 2x40 Ultra Wide-Field Binoculars — A specialised 2×40 ultra-wide-field binocular that expands the naked-eye view rather than delivering conventional high magnification. Its exceptionally broad 24° field is designed for sweeping constellations, the Milky Way, meteor activity, comets, concerts and sporting events.
An Expanded Naked-Eye View
At 2× magnification, the Gemini shows a much larger part of the sky than a conventional astronomy binocular. The 40mm objectives gather more light than the unaided eye, while the low magnification makes it easier to follow large-scale sky patterns and moving subjects.
Optical Design and Focusing
The compact Galilean optical arrangement does not use a conventional prism system. Fully multi-coated optical surfaces improve light transmission, while a large 20mm exit pupil and individual focusing allow each side to be adjusted independently.
The published field of view is 24°, equivalent to 420m at 1,000m. Close focus is 2m (6.6ft), so this model is intended primarily for medium- to long-distance subjects.
Tripod Use and Weather Protection
At only 192g, Gemini is suitable for handheld use. It is also tripod adaptable and Celestron includes a tripod adapter for longer observing sessions. The IPX4 rating provides resistance to splashing water, but the binocular is not waterproof or nitrogen filled.
Weather protection: IPX4 water resistant. It is not nitrogen filled and should not be treated as fully waterproof.
What Is Included?
- SkyMaster Gemini 2x40 binoculars
- Tripod adapter
- Neck strap
- Eyepiece cover
- Objective covers
- Cloth hard-shell zip case
- Lens-cleaning cloth
- Five-language quick setup guide
Please note: A tripod, solar filters and any item not listed above are not stated as included.
Specifications
Optics
| Optical design | Galilean binocular |
|---|---|
| Magnification | 2× |
| Objective diameter | 40mm |
| Objective focal length | Not stated |
| Angular field of view | 24° |
| Linear field of view | 420m at 1,000m |
| Exit pupil | 20mm |
| Eye relief | 10mm |
| Close focus | 2m (6.6ft) |
| Interpupillary distance | 56–72mm |
| Dioptre adjustment | -5 to +3 |
| Focusing system | Individual focus for each barrel |
| Optical coatings | Fully multi-coated |
| Prism glass | Not applicable (Galilean design) |
| Twilight factor | 8.9 |
| Relative brightness | 400 |
| Limiting stellar magnitude | 7.1 under ideal conditions |
Construction and Size
| Weather resistance | IPX4 water resistant |
|---|---|
| Nitrogen filled | No |
| Tripod mounting | Tripod adaptable; tripod adapter included |
| Carrying case | Cloth hard-shell zip case |
| Dimensions | 122 × 39 × 47mm (4.8 × 1.5 × 1.8 inches) |
| Binocular weight | 192g (6.8oz) |
Solar Safety
Warning: Never look at or near the Sun through these binoculars.
These are not solar binoculars and do not include certified solar filters. Direct or nearby views of the Sun can cause immediate and permanent eye injury.
Do not attempt solar projection and do not attach improvised or eyepiece-mounted filters.
Instruction Manual
The official Celestron documentation is provided in English, French, German, Italian and Spanish.