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Connecting Web Services

Spectrum Service



Filter Profile Services for the Virtual Observatory

Welcome to our web site dedicated to filter profile related VO services developed at the Johns Hopkins University. On these pages you will find tools and tutorials on how to access  the profiles of most of the well-known astronomical instruments.

The passband database contains the profiles of almost 100 photometric filters of several instruments including the largest and most recent ones such as the SDSS, HST, etc. The list is easily also expandable, anyone can post additional filter profiles using a web form or automatically using a client program to the web services.

The filter profile catalog can be searched by keyword and by advanced query options including effective wavelength and UCD. The results may be overplotted on each other for easy comparison of photometric systems or between different versions. Give it a try now.

About the Website

This website is intended to provide an easy to use interface to access the catalog. All the basic tasks can be done on the forms. Filter profiles may be downloaded 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. 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 Netscape Navigator. Check print preview before wasting paper!

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 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).