SkyServer: GLossary
 
Glossary
DR6 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
PrimaryThe "main" observation of an object. Because there are overlaps at many levels of the imaging (runs, stripes), an object may be observed two or more times. Whether or not a specific observation of an object is the primary is decided when chunks are resolved. Whether an object is primary or not depends on a large number of factors.