
Moon Phase Finder
Estimate the moon phase and illumination percentage for any calendar date , amateur astronomy tool.

Explore moon phases, escape velocities, planet weights, and telescope optics with browser-based space calculators.

Estimate the moon phase and illumination percentage for any calendar date , amateur astronomy tool.

Calculate escape velocity from planetary mass and radius , space physics and astronomy education tool.

Compare your Earth weight against gravity on all planets and the moon , space education tool.

Compare eyepiece magnification and field-of-view tradeoffs for any telescope setup , astronomy optics tool.

Estimate telescope magnification, true field of view, and exit pupil using aperture, focal length, and eyepiece data. It helps astronomy hobbyists compare setups before a night of observing.
249+ browser-based tools across 16 categories , all free, no sign-up required.