A monocular telescope will typically possess a lens of 20mm to 42mm. A lens that is bigger permits one to see a wider perspective. A lens that is bigger will even lead to a bigger, brighter image when looking through your monocular telescope. The downside is the bigger the lens will be , the thicker and warmer your monocular telescope will undoubtedly be. https://www.marketwatch.com/press-release/starscope-monocular-review---new-state-of-the-art-device-2020-03-03