Tools
Free calculators and interactive tools from Starvest.
Telescope Magnification Calculator: Work Out Your Real Power
Free telescope magnification calculator: enter your telescope's focal length and eyepiece to get the real magnification, the max useful power for your aperture, and the exit pupil.
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Telescope Field of View Calculator: Will the Target Fit?
Telescope field of view calculator: enter your focal length and eyepiece to get the true field of view in degrees, and see whether the Moon, Orion Nebula and other targets fit.
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Telescope Limiting Magnitude Calculator: Faintest Star You Can See
Telescope limiting magnitude calculator: enter your aperture to estimate the faintest star you can see, your light grasp versus the naked eye, and what targets come into reach.
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Bortle Scale Calculator: How Dark Is Your Sky?
Bortle scale calculator: answer a few questions about what you can see overhead to estimate your Bortle class, naked-eye limiting magnitude and what is realistically visible.
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500 Rule Calculator: Max Exposure Before Star Trails
Free 500 rule calculator for astrophotography: enter your focal length, crop factor and pixel pitch to get the longest shutter speed before stars trail, using both the 500 rule and the sharper NPF rule.
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