NED — The NASA/IPAC Extragalactic Database

The ability of NED to support automated access involving large data volumes or high query rates is limited. Such support is provided on an as-available, best-effort basis. Please keep in mind that the limited computing and network bandwidth resources are shared by thousands of users, and too many simultaneous queries can make the services unresponsive for everyone. Our goal is to provide fair use and responsive access to NED resources for the entire astronomical community and the general public. To help us with this, please conform to the following guidelines when running programs or scripts that automate access to NED:

• Please contact the NED Helpdesk before starting any set of queries that might extend over more than 6 hours.
• Do not query NED more frequently than 1 per second.
• Do not run multiple concurrent automated queries.
• Use XML(VOTable output format) whenever possible (HTML and other formats may change at any time).
• On queries that support optional image retrieval set img_stamp=NO
• On queries that support detailed information lists, set list_limit=0
• If you need multiple XML VOTable outputs, consider using of=xml_all
• Do NOT automate image retrieval - please contact the NED Helpdesk if this is essential to you.

Thank you for your cooperation.

Contact the NED helpdesk.