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Telescopes & Observation
Aperture, focal ratio, mounts, eyepieces. Honest guides to what a telescope can and cannot show you, and how to choose one you will actually use rather than one that lives in a closet.
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Featured · guide
Your First Telescope: Why Aperture Beats Magnification
The single most important spec is aperture — and the second is a mount you don't hate. Every other consideration is downstream of those two.
Dmitry Shteynbuk · January 13, 2026 · 3 min read
Articles in this hub
3 publishedTelescopes & Observation·
Eyepieces and Focal Ratio: The Math That Sets Your View
Three numbers determine what you see through any telescope: focal length, focal ratio, and eyepiece focal length. The relationships are simple — and they explain almost every eyepiece choice.
Dmitry Shteynbuk · 3 min read
/articles/eyepieces-focal-ratioTelescopes & Observation·
Refractor vs. Reflector vs. Catadioptric: Optics, Honestly Compared
The three optical designs that dominate amateur astronomy — how each one works, what it's genuinely good at, and where the trade-offs actually bite.
Dmitry Shteynbuk · 3 min read
/articles/refractor-vs-reflectorTerms to know
Full glossary →- Aperture
- The clear diameter of a telescope's main optical element.
- Focal ratio
- Focal length divided by aperture — a telescope's 'speed'.
- Focal length
- The distance from a telescope's objective to the focused image.
- Eyepiece
- The small lens assembly you look through.
- Magnification
- How many times larger the image appears versus the unaided eye.
- Seeing
- The steadiness of the atmosphere.