SkyServer: GLossary
 
Glossary
DR7 Help
 Site News
 Introduction
 Cooking with Sloan
 FAQ
 
 Query Form Guide
 SQL Tutorial
 SQL in SkyServer
 Sample SQL Queries
 Query Limits
 Searching Advice
 
 Archive Intro
 Table Descriptions
 Schema Browser
 Glossary
 Algorithms
 Web Browsers
 
 Download
 Data Publications
 API
 SkyServer Sites
 
 Contact Help Desk

nametext
magnitude, PogsonThe Pogson magnitude is the standard astronomical magnitude system, where one increment in magnitude is an increase in brightness by the fifth root of 100. A star of 1st magnitude is therefore 100 times as bright as a star of 6th magnitude. Mathematically this is expressed as
M1 - M2 = -2.5log(F1/F2)
where M1 and M2 are the magnitudes of two objects, and F1 and F2 are their luminous fluxes.