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This page offers links to recommended documentation and addresses frequently anticipated questions related to the JWST Release of the first science data.  Check the material here, your question might already be answered!

On this page...

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Frequently Asked Questions

-

about JWST

First

Data

Release

I am a PI of a (partially) executed JWST program.

When can I get my data?

Cycle-1 data started to appear in MAST beginning on 14 July 2022.

How do I authorize my Co-Is to have access to data from that program?

Direct your browser to the MyST site, and follow the instructions in the MAST Accounts page.

How do I learn

which

when JWST observations have been obtained?

There are multiple ways to discover JWST Observations. For instance:

  • To be notified when JWST data appear in the archive, become available to all users, or are reprocessed, use the subscription service in the MAST Portal.  This is the recommended way to find out when data from program IDs get ingested or receive updates.
  • In the MAST Portal, click Advanced Search, enter "JWST" in the Mission filter and enter a range of observation start dates, e.g., "2022-07-02"  and "2022-07-09in the Start Time filter boxes, then click the Search button.  This will search for all JWST observations that were started between 2 July 2022 through 9 July 2022.
  • Using the Python library astroquery.mast, form a query_criteriasearch with the parameters obs_collection="JWST" and some other parameter such as instrument_name="MIRI" . See the astroquery.mast documentation for details.

What is the usual delay between the end of an observation and when it first appears in MAST?

That is a difficult question to answer with precision. A lot of the data gets processed within an hour or two, but there are a few edge cases where it takes more than a day. But that’s after the data processing system gets all of the pieces from Flight Operations. Many hours can elapse between the end of an exposure and transmission of that data to the ground. This is largely because JWST does not have continuous contact with the ground in the high-bandwidth channel that is required to transmit high-volume science data. That said, it is likely that most data will appear in MAST within a day or two of the end of the last exposure in an observation. 

JWST Generates so many files. Which

ones

are most important?

Generally the Level-2b (calibrated) and Level-3 (calibrated and combined) products are most appropriate for science analysis. Consult the JDox article Getting Started with JWST Data for details.

The Portal won't load Observations into my Basket. What do I do?

Some Observations (i.e., rows in the Portal Search Results table) are associated with a very large number of files. Loading too many Observation into the Basket at once can result in a pop-up error message like the following:

Image Added

This problem is particularly likely for JWST Observations with many extracted spectra (e.g., NIRCam Wide-Field Slitless Spectra), or Observations containing lots of Guide-Star files (as for an extended mosaic). To get around this problem you can do the following:

  1. Select fewer Observations, then load those into the Basket, select files for download, then empty the Download Basket when finished. Repeat as necessary until you have retrieved file from all Observations of interest.
  2. Use the MAST API. See the Astroquery Search and Retrieval section of the Using MAST APIs article. Follow the link to the Jupyter Notebook for API Large Downloads.

I'm writing a paper that analyzes data from JWST. How do I create a DOI to reference the data I used?

Navigate your browser to the special DOI Portal. Follow the instructions in the Special Searches article in the Portal Guide, specifically the section on Create a DOI.


Primary Reference Sources

For Further Help...

JWST Help Desk

MAST Help Desk