Please look at the FAQ and tutorials below to see if your question has been answered. Much of what you need to know is already available:


For help on the SkyServer or CASJobs, or to know more about SQL, consult the SkyServer DR17 Support.

Accessing Data

If you want a list of tools for accessing the data, consult the data access documentation.

About the Data

If you have questions about the nature of the data (what is a plate? what is a run?) consult the spectroscopic, imaging, infrared or IFU documentation.

Data Analysis

If you have a question about a technique used in the data analysis, see if it is addressed in the algorithms documentation.

Glossary Terms

If there is a term you don't understand, try to find it in the glossary.

About SAS

If you are looking at a file from SAS and want to know more about its contents, consult the survey data model.


Frequently Asked Questions (FAQ) provides answers to common questions about the SDSS-IV, Data Release 16 and our data access tools.


Tutorials provide guidance and hands-on practice in accessing SDSS data for a variety of scientific and teaching tasks.

Contact Us

If you are unable to find answers to your questions on these pages, please email us at the SDSS helpdesk, and your question will be directed to a survey expert in the appropriate area.

How to cite SDSS

Find out more about how to cite SDSS-IV and earlier phases of SDSS, as well as a LaTeX template at How to Cite SDSS.

Please note that your SDSS helpdesk e-mail may be shared with SDSS collaboration members and contributors who we think can help answering with your question. We will retain your email and our responses for archival purposes. These questions posed may be used to guide the development of our online documentation, but no identifying or proprietary information from your email will be published in that documentation or elsewhere. We will delete your email if you request us to do so. None of the information from your email will be sold.