Focal Length & Aperture: Go Small Or Go Big?
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Understanding Focal Length: Trading Speed for Detail
22:29
Can a telescope be too big?
12:11
Astro Tutorial #1.5: Focal Length and Aperture
12:32
The Myth of the "Fast" Telescope
22:32
80% of Astrophotography Basics in 20 Minutes!
37:39
Petra (65) viaja sozinha num veículo militar 8x8 para a Índia
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Three Tests That Break the Flat Earth Cult
10:29