SDSS CasJobs is a very popular service for professional data users. It is an online workbench for large scientific catalogs, designed to emulate and enhance local free-form query access in a web environment. Some features of this application include:

(1)Both synchronous and asynchronous query execution, in the form of 'quick' and 'long' jobs.

(2)A query 'History' that records queries and their status.

(3)A server-side, personalized user database, called 'MyDB', enabling persistant table/function/procedure creation.

(4)Data sharing between users, via the 'Groups' mechanism.

(5)Data download, via MyDB table extraction, in various formats.

(6)Multiple interface options, including a browser client as well as a java-based command line tool.

Recently, CasJobs mirror system in Beijing was set up by Chinese Virtual Observatory (China-VO) team, and opened to users. In the CasJobs Beijing system, the latest SDSS DR12 catalogs and LAMOST DR1 catalogs are supported.

For more information, please visit at http://sdss.china-vo.org.