Astronomy
Astronomy calculators for telescope magnification, star magnitude, asteroid impact, exoplanet habitability, and astrophotography.
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Asteroid Impact Energy
Calculate the kinetic energy and destructive potential of an asteroid impact from diameter, velocity, and density. Estimates crater size and earthquake equivalent.
Astrophotography Exposure
Calculate the maximum untracked exposure time to avoid star trails using the NPF rule, 500 rule, and declination correction.
Binary Star Orbit
Calculate the total mass of a binary star system from orbital period and semi-major axis using Kepler's Third Law.
Exoplanet Habitability Score
Calculate the Earth Similarity Index (ESI) for an exoplanet based on radius, density, escape velocity, and surface temperature relative to Earth.
Hubble's Law Calculator
Calculate recession velocity and distance from cosmological redshift using Hubble's Law. Includes lookback time, scale factor, and relativistic corrections.
Light Travel Time
Calculate how long light takes to travel a given distance. Enter distance in AU or km and get travel time in seconds, minutes, hours, days, or years.
Solar Eclipse Timing
Calculate solar eclipse duration and umbral shadow diameter from Moon and Sun distances. Determines eclipse type, angular sizes, and maximum totality duration.
Star Magnitude Calculator
Calculate absolute magnitude from apparent magnitude and distance using the distance modulus formula. Includes luminosity ratio and parallax.
Telescope Limiting Magnitude
Calculate the faintest star visible through a telescope based on aperture and sky brightness conditions.
Telescope Magnification
Calculate telescope magnification, true field of view, exit pupil, and resolution from focal length, eyepiece, and apparent field of view.