User accounts are necessary to access protected data in MAST, and to make use of certain Portal functionality.

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Anonymous Use

Anyone can use the MAST Portal to search for hosted data. Anonymous users may retrieve any publicly-available data.

A search resulting in EAP data, showing yellow rows and a black lock icon

Be aware that recent data from active missions are often protected for an Exclusive Access Period (EAP). This is a limited period of time just after an observation, during which only authorized and authenticated users (i.e., the Investigator team) may retrieve the data.  Such protected data are designated in the Portal results table with a yellow row background and the black "lock" icon seen on the left.

User Accounts

There are some important circumstances where you will need an account for MAST:

  • Retrieval of data protected by an EAP, whether through the Portal or through scripted access
  • Viewing preview images in the Portal results table for EAP protected data
  • Subscribing to data notifications for active missions

The MAST Portal uses the same MyST Accounts used by other STScI services, such as proposal submission.  If you do not already have an account, one can be set up quickly through the MyST Portal.

MyST landing page with three columns - Create, Update, and Manage Accounts

Data Authorization

Permission to access EAP data is also controlled through your MyST Account. Principal Investigators (PI's) of observing programs are automatically granted access to this data.  PIs of programs may also authorize other users to access the data during the EAP period by navigating to the MyST Home screen and selecting the Update Your Account option. From there click the Manage Access to Exclusive-Access Science Data menu option, select your program, and enter the MyST email address of record for your colleague.

Login info and button


Be sure to login to the Portal before attempting to retrieve EAP data, or before attempting to subscribe to data notifications. Just click the Login... text.

Logout button


If for security reasons you must log out of a Portal session (e.g., if you are obliged to share your workstation), go to That page will contain an entry for each active MAST session for which you are logged in. Click the Log Out button to terminate the session in question. Then visit the SSO portal to log out of the MyST system:

Another option is to use an Incognito (or Private) browser instance when using the Portal. Logging out would be as simple as closing the Incognito window. The next user can login with another incognito window to start a fresh session.


MAST also offers API token authorization for programmatic access to EAP data.  Users with a MyST Account can find instructions on creating and using these tokens on the auth.MAST documentation page.  With a valid token in place, authorized users will then be able to retrieve MAST EAP data through Astroquery or cURL scripts. See the video on Using Auth.AST Tokens in the Demos and Tutorials chapter. The steps are simply:

  1. Navigate to the Tokens page and click the  button.
  2. Record the long, alpha-numeric string in the environment variable $MAST_API_TOKEN, preferably in your .bashrc file.

Be aware that API tokens will expire after 10 days of inactivity or 60 days after creation, whichever comes first.  Users experiencing any trouble with existing tokens should first try generating new ones.

Data Use | Acknowledgements | DOI | Privacy

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