Aperture, focal length and focal ratio - Optics Trade Blog
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Confused with scope focal length - what am I missing? - Beginners Forum (No Astrophotography) - Cloudy Nights
astronomical optics, part 2: telescope & eyepiece combined
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Simple Formulas for the Telescope Owner - Sky & Telescope - Sky & Telescope
Everything You Need to Know Before Buying a Telescope | B&H eXplora
Telescope stats explained | BBC Sky at Night Magazine
Children's beginner's 70mm aperture 400mm focal length astronomical refracting telescope-with carrying bag, adjustable tripod travel telescope - KENTFAITH
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Telescope Equations: Magnification
what telescope should i look for?
what telescope should i look for?
Telescope Equations: Magnification
How to Build a Telescope ?
Telescope Focal Length Explained - YouTube
Focal Length | Imaging the Universe - The University of Iowa
Why does the focal length of a telescope have an effect on the magnification? - Astronomy Stack Exchange
How to Choose A Telescope for Astronomy | Types of Telescopes - Sky & Telescope
