SVBONY SV135 1.25″ 7–21mm 60°–40° Zoom Eyepiece

Product Overview

The SVBONY SV135 60°–40° (item W9105D) is a fully multi-coated 1.25″ zoom eyepiece that runs continuously from 7 mm to 21 mm. It is the widest-field SV135, with a 60° apparent field at 7 mm and 40° at 21 mm, from seven elements in four groups of high-index glass. Eye relief is 13–15 mm, the barrel has an M28.5 × 0.6 filter thread, and it weighs 145 g.

Who It's For

This is a good match if you want one eyepiece for the Moon, Jupiter and Saturn, nebulae and star clusters, and you value a wider field at high power — helpful for keeping a planet in view longer on a manual or undriven mount.

Key Features & Design

• 7–21 mm linear zoom with a 60°–40° apparent field.
• 4 groups / 7 elements: fully multi-coated high-index glass.
• 13–15 mm eye relief: rubber eye guard for comfort with glasses and to block stray light.
• Safety undercut barrel: helps keep it seated in the focuser or diagonal.
• Blackened lens edges and anti-reflection threads.
• M28.5 × 0.6 filter thread for 1.25″ accessories.

Optical Design

With seven elements in four groups, this SV135 holds a wider field across the zoom range than the five- and six-element versions: 60° at 7 mm, 40° at 21 mm. The trade is weight — 145 g against 95 g and 133 g for the other two. On a 1000 mm telescope it gives roughly 48× to 143×.

Recommended Uses

• Moon and planets: Jupiter and Saturn at the power the seeing allows.
• Nebulae and star clusters, including diffuse nebulae, at the low-power end.
• Grab-and-go and outreach: one eyepiece in place of several.

Compatibility and Accessory Notes

• Barrel: 1.25″, for standard 1.25″ focusers and diagonals.
• Filters: M28.5 × 0.6 thread, compatible with 1.25″ filters.

Good to Know Before You Order

• Field narrows to 40° at 21 mm, as is typical of zooms.
• Three SV135 versions: 52°–36°, 57°–40° and 60°–40° (this one), each with its own design and weight.

Frequently Asked Questions

Is it difficult to set up?

No. It slides into a 1.25″ focuser or diagonal; twist to zoom and refocus slightly as needed.

Can I use it with glasses?

The 13–15 mm eye relief and rubber eye guard are designed for use with glasses.

Which SV135 has the widest field?

This one: 60° at 7 mm and 40° at 21 mm.

Bottom Line

In short: a 145 g, 4-group/7-element 1.25″ 7–21 mm zoom with a 60°–40° field — the widest-field SV135 for lunar, planetary and cluster observing.