UnitfulAstro.jl Documentation

UnitfulAstro.jl is an extension of Unitful.jl to include units commonly encountered in astronomy.

Table of Units

The list of additional units is given below:

Examples

julia> using Unitful, UnitfulAstro

julia> uconvert(u"erg", 1 * Unitful.kg * Unitful.gn * Unitful.m)
9.80665e7 erg

julia> uconvert(u"Jy", 1.23e-20 * u"erg/s/cm^2/Hz")
1230.0000000000002 Jy

julia> uconvert(u"ly", 1 * u"pc")
3.2615637771674333 ly

Magnitudes

Currently only AB, bolometric, Johnson, and Gunn magnitudes are supported.

For example

julia> using Unitful, UnitfulAstro
    
julia> u = UnitfulAstro;

julia> 5*u.AB_mag + 5*u.AB_mag
4.247425010840047 AB mag

julia> 5*u.U_mag/100
10.0 Johnson U mag

julia> 5*u.g_mag + 10*u.Jy # magnitudes can be mixed with ordinary linear units
47.300000000000004 Jy

julia> uconvert(u.AB_mag, 1*u.μJy) # converting one μJy to AB magnitudes
23.90006562228223 AB mag

julia> uconvert(u.bol_mag, 1*u.Ssun) # apparent bolometric magnitude of the Sun
-26.83199694276591 bol mag

julia> uconvert(u.bol_Mag, 1*u.Lsun) # absolute bolometric magnitude of the Sun
4.7399959339194595 bol Mag

Color

Color index is also supported

julia> using UnitfulAstro

julia> u = UnitfulAstro;

julia> 1u.B_mag - 0.5u.V_mag
0.4999999999999999

Note: that the only operation that can happen between different bands is subtraction

julia> using UnitfulAstro

julia> u = UnitfulAstro;

julia> 1u.B_mag + 0.5u.V_mag
ERROR: MagnitudeError: an invalid operation was attempted with magnitudes: 0.9999999999999999 Johnson B mag, 0.5 Johnson V mag

and that + and - work on individual bands

julia> using UnitfulAstro

julia> u = UnitfulAstro;

julia> 1u.B_mag - 1.5u.B_mag
2.0823085833406205 Johnson B mag

julia> 1u.B_mag + 1.5u.B_mag
0.46889349301415084 Johnson B mag

IAU Resolutions

Copies of recent IAU resolutions which formalize the definitions of some units used in this package are linked below.

• IAU 2012 (pdf)
• IAU 2015 (pdf)