After a successful search for data, and browsing to determine which observations are of interest, the next step is to select particular data products for download. Since JWST provides many files per observation (often hundreds, or even thousands), it is especially important to choose carefully the products that are most relevant for your science goals.
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Selecting Data
To select data for detailed Browsing Data and/or placing results in the Download Basket, simply check one or more boxes at the far left of the results table (seen in the pink circle in Figure 1) to select them (or select all rows by checking the box in the table heading, shown in the blue circle), then click the desired action button. Multiple data products in the Download Basket may be further refined with the Download Manager and selected for retrieval.
See Retrieving Data for various download options.
Minimum Recommended Products (MRP), Intermediate Products
The MAST Portal offers various data product categories such as intermediate associated data products, calibration reference files, and other auxiliary products (e.g., guide star products and processing logs) as well as science products. A subset of calibration pipeline products essential for extracting science data is called the "Minimum Recommended Products" (MRP). The Portal Download basket, by default, selects Minimum Recommended Products with a Filter checkbox. Note that MRP excludes calibration reference files, preview images, and guide-star data products.
Calibration Reference Files
The JWST Science Calibration Pipeline (referred to as “the pipeline”) uses calibration reference files to create the science products. The reference files contain different types of calibration data or information depending on instruments and observing modes (spectroscopic, imaging, coronagraphic, aperture masking interferometry, and time series observation). They are periodically updated based on the improvement and updates of data processing stages.
The most recent calibration reference files can be retrieved via MAST Portal. If all intermediate products such as calibration reference files and other auxiliary products are needed for download, uncheck the MRP filter check box in Figure 2. Select files of interest in the Files panel and click the Retrieve References button (Note that this button is only enabled when the MRP filter box is unchecked.).
For the step-by-step guide for reference product retrieval, see the MAST Portal Guide chapter on retrieving Calibration Reference Files.
Information about all the calibration reference files can be found at the JWST pipeline Reference File Information, such as file naming convention and file types. If seasoned users may want to (re-)run the pipelines (different versions of the pipelines or reprocess data multiple times to change reference files), see how to run the pipeline: Running From the Command Line or Running From Within Python.
Auxiliary Products
Auxiliary products include Guide star data products, processing logs, pre-images for target selection, Micro-shutter array metadata, telemetry files, etc. These data can be retrieved by unchecking the MRP checkbox.