Telescope Aperture and Magnification Chart
Stargazer Nest · stargazernest.com · reviewed September 13, 2026
| 70 mm (2.75 in) | about 140x |
|---|---|
| 90 mm (3.5 in) | about 180x |
| 114 mm (4.5 in) | about 228x |
| 150 mm (6 in) | about 300x |
| 200 mm (8 in) | about 400x, seeing often caps it near 250-300x |
| 250 mm (10 in) and up | 500x+ in theory, air limits most nights |
| Rule of thumb | about 50x per inch or 2x per mm of aperture |
| Magnification | telescope focal length ÷ eyepiece focal length |
Typical values for general guidance. Always check the manufacturer's specification for your exact product.
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