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astronomical optics, part 3: the astronomical image
Light Vortex Astronomy - Article: How to Very Accurately Calculate your Telescope's Effective Focal Length
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Light Vortex Astronomy - Article: How to Very Accurately Calculate your Telescope's Effective Focal Length
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astronomical optics, part 2: telescope & eyepiece combined
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Dome Calculation - the homepage of Nicolàs de Hilster, PhD
Astro Tutorial #1.6: THE F-RATIO "fast" vs "slow" scopes - YouTube
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