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Astronomical distance calculators
Explore light time, parallax and distance-related magnitude.
Choose the right calculation
A light-time calculation uses vacuum propagation speed. Parallax angle must use the stated angular unit. Simple inverse-parallax estimates can be unreliable when measurement uncertainty is large relative to the parallax.
Find a tool for your question
Light Travel Time Calculator
Find time for light to travel a vacuum distance expressed in kilometres.
Parallax Distance Calculator
Estimate stellar distance from annual parallax angle in arcseconds.
Distance Modulus Calculator
Find distance modulus from a distance expressed in parsecs.
Magnitude Flux Ratio Calculator
Compare received flux from a difference in astronomical magnitudes.
Magnitude Difference From Flux Calculator
Convert an astronomical flux ratio into a magnitude difference.
Distance From Modulus Calculator
Recover astronomical distance from an entered distance modulus.
Redshift From Wavelength Calculator
Compare an observed spectral wavelength with its rest wavelength.
Observed Wavelength From Redshift Calculator
Find observed wavelength for a stated rest wavelength and redshift.
Are a parsec and a light-year the same unit?
No. Both measure astronomical distance but use different definitions. A parsec is defined through the parallax relationship.
Useful next steps in other categories
Frequency Calculator
Find frequency from the period of one repeating cycle.
Degrees to Radians Converter
Convert degrees to radians with an explicit conversion factor.