Tools
Free calculators and interactive tools from Starvest.
All Tools guides & reviews
Tools
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.
Tools
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.
Tools
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.
Tools
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.