Please explain focal ratio vs. exposure time - Beginning Deep Sky Imaging - Cloudy Nights
Telescope Equations: Magnification
Image Resolution: Effect of Focal Ratio - Beginning Deep Sky Imaging - Cloudy Nights
Telescope stats explained - BBC Sky at Night Magazine
Aperture, focal length and focal ratio - Optics Trade Blog
Which Telescope is Best for Me? — Starizona
what telescope should i look for?
Telescope Equations: Minimum Magnification
Focal Ratio vs. Aperture: What Makes an Object Look Brighter Through a Telescope? - Sky & Telescope - Sky & Telescope
How Fast is Your Telescope?
Simple Formulas for the Telescope Owner - Sky & Telescope - Sky & Telescope
f-ratio myth
Lecture 3
Laser Beam Expanders | Edmund Optics
The Big Red One: My Optimized 6-inch f/9 Reflector - Gary Seronik
Tele Vue Optics: Imaging Methods
Focal length in detail - Beginners Forum (No astrophotography) - Cloudy Nights
Confused with scope focal length - what am I missing? - Beginners Forum (No astrophotography) - Cloudy Nights
what telescope should i look for?
How Focal Ratio Affects Your Astro Images - Sky & Telescope - Sky & Telescope
PPLATO | FLAP | PHYS 6.4: Optical instruments
h-alpha and white light sun images
What is Focal Length – Distance Light Travels in Telescopes
Optical system of a telescope
focal ratio – Society for Popular Astronomy
