Sky-Watcher Emerald 9mm 82° 1.25" Eyepiece

Product Overview

The Sky-Watcher Emerald 9mm 82° 1.25-inch Eyepiece is an ultra-wide visual astronomy eyepiece designed for immersive, high-magnification observing. With an 82° apparent field of view, 7-element optical design, 8mm eye relief, filter threading, and an included carry case, it gives observers a wide, engaging view while keeping the eyepiece compact and easy to use.

Who Is This Product Best For?

This eyepiece is best for visual observers who want a wider apparent field than standard Plössl-style eyepieces, especially for lunar observing, planetary viewing, double stars, globular clusters, and smaller deep-sky targets. It is suitable for beginner-to-intermediate observers upgrading their eyepiece kit, as well as experienced observers who want a compact ultra-wide 1.25-inch eyepiece.

Why Choose This Product?

• Ultra-wide 82° view: Gives a more immersive observing experience and keeps objects in view longer on manual mounts.
• 9mm focal length: Useful for higher magnification on the Moon, planets, double stars, and compact deep-sky objects.
• 1.25-inch compatibility: Works with common 1.25-inch focusers, diagonals, and filter systems.
• 7-element optical design: Built for wide-field performance in a compact visual eyepiece.
• Included carry case: Helps protect the eyepiece during storage and transport.

Recommended Uses

• Lunar and planetary observing.
• Double stars and compact star clusters.
• Higher-power views in refractors, Maksutovs, Schmidt-Cassegrains, Newtonians, and Dobsonians.
• Manual telescope users who benefit from a wider field of view.
• Visual observing with compatible 1.25-inch filters.

Compatibility and Accessory Notes

The 9mm Emerald uses a 1.25-inch barrel and is threaded for compatible 1.25-inch filters. It can be used with telescopes that accept 1.25-inch eyepieces through the focuser or diagonal. As with any high-power eyepiece, final magnification depends on the telescope focal length.

Important Limitations

• Shorter eye relief: The 9mm version has 8mm eye relief, which may be tight for observers who wear glasses.
• Higher magnification: Performance depends on seeing conditions and telescope optics.
• Visual use: This is an eyepiece for visual observing, not a camera adapter or imaging accessory.

Frequently Asked Questions

Is this eyepiece good for beginners?

Yes. It is a strong upgrade for beginners who want a wider, more immersive view than typical kit eyepieces, though the 9mm focal length is best used when seeing conditions support higher magnification.

What is it best used for?

It is best used for the Moon, planets, double stars, globular clusters, and compact deep-sky targets.

Will it fit my telescope?

It will fit telescopes that accept standard 1.25-inch eyepieces.

Can I use filters with it?

Yes. The eyepiece is threaded for compatible 1.25-inch filters.

When should I choose a different focal length?

Choose the 16mm or 22mm Emerald if you want lower magnification, a brighter view, or a wider true field for larger objects.

Our Recommendation

Ontario Telescope recommends the Sky-Watcher Emerald 9mm 82° eyepiece for observers who want a compact ultra-wide eyepiece for higher-power visual observing. It is especially useful when you want more field of view than a standard short focal length eyepiece while still using a 1.25-inch format.