iOptron 10 mm & 25 mm Plossl Eyepiece Set for Beginners
By TelescopesPlus - The #1 Online Store for Telescopes and Accessories | Published: 2026-10-29
Category: Buying Guides
A practical look at the iOptron 10 mm & 25 mm Plossl eyepiece set: what each focal length does, who it suits, and when to skip it.
Quick answer
For most beginners, the iOptron 10 mm & 25 mm Plossl eyepiece set is a smart, low-cost way to get two useful magnifications. The 25 mm gives wide, bright views for finding targets, while the 10 mm zooms in for closer looks—just remember the 10 mm may be too powerful for small or low-quality telescopes.
Why two eyepieces beat one
A single eyepiece limits what you can see. The 25 mm gives a lower magnification that makes it easier to locate objects and keeps images bright, which is ideal for sweeping star fields or viewing the Moon. The 10 mm offers higher magnification for details like lunar craters or Jupiter's moons, but it narrows the field and can make objects drift faster.
Having both lets you start with the 25 mm to center an object, then switch to the 10 mm for a closer view. This is a practical workflow that works with most telescopes that accept 1.25" eyepieces.
Know your telescope's limits
The 10 mm eyepiece may push magnification too high for telescopes with short focal lengths or small apertures. If your telescope's maximum useful magnification is around 100x, a 10 mm eyepiece might exceed it, resulting in dim or blurry views. Check your telescope's specs to see if the 10 mm is a good match.
The 25 mm is generally safe for any telescope that accepts 1.25" eyepieces, making it a reliable starting point.
How to decide if this set is right for you
- Check your telescope's focal length: Divide your telescope's focal length (in mm) by 10 and by 25 to see the magnifications you'll get. If the 10 mm result exceeds your telescope's maximum useful magnification (usually about 2x the aperture in mm), the 10 mm may be too powerful. If the 10 mm is too powerful, consider a 15 mm or 20 mm eyepiece instead.
- Match the eyepiece to the target: Use the 25 mm for finding objects and for extended views of the Moon, star clusters, or the Milky Way. Switch to the 10 mm for close-ups of the Moon, planets, or double stars when the atmosphere is steady.
- Consider your upgrade path: This set is a budget-friendly way to get started, but if you already own a 25 mm eyepiece, you might only need a 10 mm. If you plan to grow your collection, a single higher-quality eyepiece might be a better long-term investment. If you already have a low-power eyepiece, look for a single high-power option instead of a full set.
Product facts
- iOptron 10 mm & 25 mm Plossl Eyepiece Set - TP100: This set includes a 10 mm and a 25 mm eyepiece, both with standard 1.25" barrels that fit most diagonals or focusers. You can use these eyepieces with a wide range of telescopes, so you don't need to worry about compatibility if your scope accepts 1.25" accessories.
iOptron 10 mm & 25 mm Plossl Eyepiece Set - TP100 - iOptron 10 mm & 25 mm Plossl Eyepiece Set - TP100: The Plossls feature a medium field of view with a 50° apparent field of view. The 50° field is typical for Plossls and gives a comfortable, classic view, but it's narrower than premium wide-angle eyepieces, so you'll see less sky at a glance.
Who should buy this set
Best for
- Beginners with a telescope that accepts 1.25" eyepieces and who want two useful magnifications without spending much.
- Owners of short-focal-length telescopes (like 400–700 mm) where the 10 mm provides moderate magnification.
Not for
- Advanced observers who need wide apparent fields or specialty eyepieces for planetary or deep-sky work.
- Telescopes with very short focal lengths where the 10 mm exceeds the maximum useful magnification.
