Astronomy & Space

Free 500 Rule Calculator for astrophotography — instantly find the maximum shutter speed to avoid star trails using the 500 rule, NPF rule, and all rule variants for any camera sensor.

Free Astrophotography Exposure Calculator — compute the maximum untracked shutter speed using the 500 Rule, 400 Rule, 300 Rule, NPF Rule, and Plate Scale method, plus SNR-based sub-exposure planning for tracked deep-sky imaging.

Free Delta-V (Δv) rocket equation calculator using the Tsiolkovsky equation. Solve for velocity change, initial mass, final mass, or Isp with multi-stage support, engine presets, and mission budgets.

Free Habitable Zone (HZ) Calculator using Kopparapu et al. (2013/2014) polynomial model — compute conservative and optimistic HZ boundaries, equilibrium temperature, stellar lifetime, snow line, ESI score, and more for any star.

Free Hohmann Transfer Orbit Calculator — compute delta-V burns, transfer time, orbital velocities, and propellant mass for transfers between two circular orbits or between planets.

Free Hubble Constant (H₀) Calculator — solve Hubble's Law bidirectionally for recession velocity, distance, redshift, and universe age with spectral line presets.

Free Light Year to Parsec Converter — instantly convert between light-years (ly), parsecs (pc), kiloparsecs (kpc), megaparsecs (Mpc), gigaparsecs (Gpc), astronomical units (AU), kilometers, and miles. Includes all-unit breakdown, cosmic scale indicator, famous distances reference, light travel time, parallax converter, and preset famous astronomical objects.

Free Lunar Eclipse Calculator — browse upcoming total, partial, and penumbral lunar eclipses from 2026 to 2032 with contact times, magnitude, visibility regions, and local time conversion.

Free Moon Phase Calculator — instantly find the current lunar phase for any date, including illumination percentage, moon age, upcoming phases, gardening guidance, and more.

Free Planet Orbital Period Calculator using Kepler's Third Law — compute orbital period, semi-major axis, or central body mass for any planet, moon, or exoplanet orbiting any star.

Free Stellar Parallax Distance Calculator — convert parallax angles to distances in parsecs, light-years, AU, and km. Includes preset famous stars, bidirectional mode, distance modulus, and precision tier analysis.

Free cosmological Redshift Calculator — compute recession velocity, luminosity distance, lookback time, and more from spectral wavelengths or redshift z using the ΛCDM model with Planck 2018 parameters.

Free Schwarzschild Radius (event horizon) calculator — compute the critical radius at which any mass becomes a black hole, surface gravity, average density, Hawking temperature, photon sphere, and ISCO radius.

Free Solar Eclipse Calculator — browse upcoming solar eclipses from 2025 to 2030, explore eclipse types (total, annular, partial, hybrid), view magnitude and obscuration data, contact times, Saros series, and countdown to the next solar eclipse event.

Free Sunrise and Sunset Calculator — find exact sunrise, sunset, solar noon, twilight, golden hour, and blue hour times for any location and date using the Jean Meeus / NOAA solar algorithm.