1. The problem statement, all variables and given/known data Simply want to know how to convert between mag arcsec-2 to solar luminosities per square parsec. 2. Relevant equations (from wiki) 3. The attempt at a solution If the surface brightness S (B band) is 27 mag per square arcseconds, then to solve for the brightness in solar luminosities per sq. pc, it'd just be the absolute magnitude of the Sun in the B band + 21.572 - 2.5log(the value I want) = 27 mag arcsec-2? Cause that doesn't work, haha. I'm terrible at conversions. Any suggestions? Thank you.