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NOTE: Most of the High Level Science Products are unavailable while unscheduled maintenance is being performed. They will be incrementally restored over the course of this week. We apologize for any inconvenience.

Getting Started

Finding Data

List of all MAST searches and tools

MAST provides several ways to find data of interest and they are listed on a "searches" web page for your convenience. Each mission has a specialized search form.

MAST provides several cross-mission searches. Use the Discovery Portal for cross-mission searches and to cross-correlate a catalog downloaded from VizieR with MAST missions.

In addition to raw data from the missions, MAST archives "High-Level Science Products": fully processed (reduced, co-added, cosmic-ray cleaned etc.) images and spectra that are ready for scientific analysis. We have provided several ways to find HLSP of interest including a search by type of data and target.

If you plan to submit large search requests, or retrieve a large number of data sets (e.g., thousands of files), please see the submitting large requests page.

Obtaining Data

Data Archive and Distribution Service (DADS)

HST data are stored within the original HST archiving system called DADS. Users request data after selecting observations of interest from the search results on the web or via StarView. HST data will be retrieved (and in the case of the newer HST instruments) reprocessed with the most current calibrations and staged to the users disk or to an ftp area on this server. FUSE and Kepler data, which are all now public, can either be retrieved online or from DADS but no reprocessing is involved. Data from the active HST instruments are reprocessed with the most recent calibrations. The current mean retrieval time can be found on the archive status page.

HST, FUSE and Kepler data may also be distributed on DVD or CD. A Guest Observer requesting proprietary data from an HST observing program must be a registered user to obtain this data. Non-proprietary data may be retrieved without registering, although users may always use their registered username, or, as of April 2015, their STScI Single Sign-On (SSO) account.

Other MAST data and HLSP

All MAST data other than HST and all the HLSP are stored on spinning disk. Users may select desired data from the search results pages for most MAST missions and download the data directly to disk via their browsers. See the summary of HLSP downloads options for more information.

If you don't quickly find the information you need, try the site search. You may also email us at