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Spectrum Services for the Virtual Observatory

Welcome to our web site dedicated to spectrum related VO services developed at the Johns Hopkins University . On these pages you will find tools and tutorials on how to access more than 1,000,000 spectra from the Sloan Digital Sky Survey (SDSS DR6). The services are open to everyone to publish their own spectra in the same framework. Reading the tutorials on XML Web Services, you can learn how to integrate the  spectrum and passband database with your programs with few lines of code.

New Features

  • Query remote data sources in parallel using the standard web service interface
  • Browse and select result for further processing in an easy way
  • Navigate between parameter forms with Next and Back button
  • Finish button will give back results calculated with default parameters in seconds
  • On-the-fly dereddening using Schlegel's dust maps
  • Continuum and line fitting using different template sets
  • Pricipal Component Analysis tools
  • Similar spectrum search

Spectrum catalog

Version 3.1 only contains SDSS DR6 spectra, but we are working on upgrading older datasets:

The spectrum catalog has a growing selection of spectra data from several surveys. It currently contains the complete SDSS DR1, DR2, DR3, 2dFGRS spectrum catalog. The collection is expandable: you can add your own spectra using the web site or the web services.

The search tools include simple ones e.g. select a redshift range as well as more advanced ones, where the selection of spectra may be refined. Keeping with the VO standard ConeSearch, one can also select objects in a given virtual pointing allowing to find objects by their RA, Dec coordinates.

About the Website

This website is intended to provide an easy to use interface to access the catalogs. All the basic tasks can be done on the forms. The site provides several visualisation and computational tools, for example building a composite spectrum from the results of a selection, which may be downloaded as well in several standard formats such as plain ascii, XML and VOTable.


Every tool published on these pages may be also accessed programmatically via XML Web Services. We recommend you try the VO way and test drive our webservices and take advantage of them to automate (for example) the upload of large amount of filter profiles and spectra. Read the tutorial here to get started. For more details visit and   

How to print out these pages?

The website is 770 pixels wide. To print on a Letter or A/4 size sheet, you should set the printing margins on both sides to 0.4 inch or 1 cm in Internet Explorer or Mozilla/Firefox.

How to become a registered user?

You can query the database and use webservices without being a registered user. If you want to post your own filter profiles or spectra to the database, please use the register link on the top of the page to get your username, password and WebServiceId (required for using the webservices via SOAP).

Referencing us

Please reference the following paper if you're doing science using Spectrum Services:

Dobos, L., Budavári, T., Csabai, I., & Szalay, A.S. 2004, "Spectrum and Bandpass Services for the Virtual Observatory", Astronomical Data Analysis Software and Systems (ADASS) XIII, 314, 185


This work was partly supported by:
OTKA-T047244, MSRC-2005-038 and MRTN-CT-2004-503929