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Astronomy Calculators
Schwarzschild Radius
Hill Sphere Radius
Escape Velocity
Mass of a Black Hole
Density of a Sphere
Mass of a Sphere
Kepler's 3
^{rd}
Law
formula
T² = (4π • R³)/(G • M)
(M) - mass of the system
.
(T) - period of the orbit
.
(R) - separation distance between the two objects
.
(G) - universal gravity constant
Small Angle Formula
Small Angle Formula
α = S / D
(α) - angle
(D) - distance to astronomical object
(S) - size or diameter of astronomical object
Flux and Magnitude formulas
Change in Magnitude from Flux Ratio
Flux Ratio from Magnitudes
Telescope formulas
Resolving Power of a Telescope
Magnification of a Telescope
Mass formulas
Mass from Luminosity
Mass from Acceleration and Radius
Mass from Speed and Separation
Mass of extra-solar planet from mass of star, radius of star orbit and radius of exoplanet orbit
Mass of extra-solar planet from mass and velocity of star and velocity of planet
Relative Size Formulas
Relative Size from Relative Temperature and Luminosity
Relative Temperature from Relative Size and Luminosity
Relative Luminosity from Relative Temperature and Size
Wavelength Formulas
Velocity from shift in Wavelength and Unshifted Wavelength
Wavelength Shift from Wavelength and Speed
Blackbody Wavelength from Temperature
Blackbody Temperature from Peak Wavelength
Photon Energy from Wavelength
Photon Wavelength from Energy
Luminosity and other Formulas
Distance from absolute and apparent magnitude
Radius from Speed and Period
Speed of Circular Motion
Hubble Time
Luminosity from Mass
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