DR2 Tools
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 Visual Tools
     - Radial
     - Rectangular
     - SQL
     - Imaging Query
     - Spectro Query
 Object Crossid
You can search the SDSS database by using several predefined queries to find specific objects. The query pages take the information you enter and create a query in the Structured Query Language (SQL). You send this query to the database by clicking on the Submit button. The database returns the information matching the criteria you entered, in the format you requested.

To search the database, select one of the following queries

  • Radial:  Search the sky around a given point.
  • Rectangular:  Search the sky in a rectangular region
  • SQL:  Type in a SQL query directly
  • Imaging Query :  Form-based query on imaging data
  • Spectro Query :  Form-based query on spectroscopic data

The names and units of fields on the query pages

  • ra, dec are the sky coordinates of the search.
    • They can be entered either in degrees or in the h:m:s, d:m:s notation.
  • radius is the search radius for a radial query.
    • It is measured in minutes of arc.
  • u,g,r,i,z are the magnitudes of the objects in the SDSS.
    • These represent the fluxes of light measured in logarithmic units, through various wavebands from the ultraviolet to the infrared

The output options and formats on the query pages

  • Return: the number of objects
    • Selecting all will return all objects
    • Selecting top N will return the first N objects satisfying the query
  • Format: the output format
    • It can be HTML, when a formatted web page is returned
    • It can be CSV, when a comma separated, unformatted text is returned, with one header line and subsequent objects in a new line, attributed separated by a comma
    • It can be XML, not yet implemented