Magnitudo mutlak

Magnitudo mutlak ${\displaystyle M\!\,}$ hiji obyék bisa diitung kalawan liwat magnitudo semu ${\displaystyle m\!\,}$ jeung jarak luminositas ${\displaystyle D_{L}\!\,}$ :

${\displaystyle M=m-5((\log _{10}{D_{L}})-1)\!\,}$

Anu mana ${\displaystyle D_{L}\!\,}$ nyaéta jarak luminositas dina parsec, (jarak 1 parsec = 3.2616 taun cahya.

Magnitudo mutlak ${\displaystyle M\!\,}$ bisa ogé diitung kalawan ngagunakeun magnitudo semu ${\displaystyle m\!\,}$ jeung jarak modulus ${\displaystyle \mu \!\,}$ :

${\displaystyle M=m-{\mu }.\!\,}$

Rigel mibanda magnitudo semu gedéna ${\displaystyle m_{V}=0.18}$ jeung jarak 773 taun cahya

${\displaystyle M_{V}=0.18-5\cdot \left(\log _{10}{\frac {773}{3.2616}}-1\right)=-6.7.}$

Vega mibanda paralaks gedéna 0.129", jeung magnitudo semu gedéna +0.03

${\displaystyle M_{V}=0.03+5\cdot (1+\log _{10}{0.129})=+0.6.}$

Alpha Centauri mibanda paralaks gedéna 0.742" jeung magnitudo semu gedéna −0.01

${\displaystyle M_{V}=-0.01+5\cdot (1+\log _{10}{0.742})=+4.3.}$

Galaksi mata hideung mibanda magnitudo semu m_V=+9.36 jeung jarak modulus of 31.06.

${\displaystyle M_{V}=9.36-31.06=-21.7.}$