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The Pandeia Engine is a Python module (compatible with Python 3.6 and later) that functions as the computational engine of the JWST ETC and Roman ETC. It can be imported and run as a standalone module.
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where "calculation" is a hierarchical input dictionary describing a scene of sources, an instrument setup, and an extraction strategy, and "result" is a hierarchical output dictionary.
Such input dictionaries are available in JWST Webapp download files (as a JSON-formatted file named input.json, suitable for reading in with the built-in Python 'json' module), or default versions can can be created with the function build_default_calc(), which creates a default dictionary, and then edited:
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from pandeia.engine import calc_utils
calculation = calc_utils.build_default_calc("jwstroman","nircamwfi","sw_imaging") |
The command above produces the NIRCam SW WFI Imaging calculation below.
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In the event that there is a typo in the mode name ("sw_imaging", above), the function will substitute the default mode for that instrument. |
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The full API documentation, with all possible options and combinations for any instrument, can be found in this file.
Examples
The following calculation defines a JWST NIRCam observation in SW Imaging mode using the full subarray and rapid readout pattern and f070w filter, for a flat-spectrum (in fnu) point source normalized to 0.001 mJy, intended to be observed with a 0.2" aperture. Note that it specifies a background precomputed for a specific date and celestial location; actual user-configured backgrounds are available in the JWST web ETC (and can be downloaded from there)
(click here to download as a JSON file: sw_f070w_rapid_full.jeng)
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| language | js |
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| title | JWST NIRCam SW Imaging |
| collapse | true |
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Example
The following dictionary defines a Roman WFI Imaging observation with the F062 filter, imaging subarray (for a 3.04s read time), medium8 readout pattern, and 6 groups; for a 0.001 mJy flat-spectrum point source (in fnu) intended to be observed with a 0.2" aperture.
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