DR3 Help
 Archive Intro
 Table Descriptions
 Schema Browser
 Introduction to SQL
 Form Query User Guide
 Query Limits
 How To
 SkyServer Sites
 SkyServer Traffic Page
 Web Browsers
 Site News
 Contact Help Desk

holeA field or set of fields which is missing from the data, either because of non-photometric conditions, tracking problems, very poor seeing, or simply because that area has not been surveyed yet. This is encoded in the status flags.