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The Pandeia engine of the Exposure Time Calculator is released to the community to support users who wish to script their calculations, run more extensive parameter space studies, and have more direct control of their scenes. We also recognize that the community has developed more extensive wrappers and public tools that depend on the Pandeia engine.
This page is intended to facilitate communication with developers in the community with Pandeia engine dependencies.
The latest release of the Pandeia engine is 12.70.
- Get the latest engine release software, installable with pip
- See the installation instructions
- Get the Synphot data files that support certain target spectra manipulations
- Get the required mission-specific items:
Webb | Roman |
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- View usage instructions (Webb-specific)
- View the Input API documentation
- View the Output API documentation
Next Planned Release
The next release of the Pandeia Engine is expected between November 30 and December 7, 2022. The currently available engine release does NOT contain any post-commissioning data.
The next release will require Python 3.8+, as a result of Astropy 5.0
title | v2.0 alpha release for developers |
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to
the regular external input API apart from a change to the meaning of the aperture_size and sky_annulus parameters. They now refer to the full-height of the aperture and a full-span distance; see JETC-2678 for more details.In brief -* If you are using the Pandeia Engine by passing it an input dictionary via perform_calculation.perform_calculation(), you MAY not
be
affected by the changes.* If your code uses the Pandeia Engine as a library and uses (in particular, but not limited to) the Scene, Source, ConvolvedSceneCube, PSFLibrary, or AdvancedPSF classes, you may need to make significant changes to your code.
THIS CODE AND DATA PACKAGE DOES NOT CONTAIN ANY POST-COMMISSIONING DATA.
This code is being distributed to the communityfor
development purposes only and is not approved for scientific use. Developers should not make releases based on this alpha release. This code is not feature-complete, and there will be other major and minor changes prior to the actual 2.0 release.Engine: v2.0alpha (or pip install -i https://test.pypi.org/simple/ pandeia.engine==2.0a0
)
Combined JWST & Roman Data, Release notes, Known Issues
Also requires the Synphot dataset.
Release was developed with Python 3.10, numpy 1.21.2, scipy 1.7.3, astropy 5.0.4, photutils 1.4.0, synphot 1.1.0, stsynphot 1.1.0
the Cycle 3 call for proposals.
We will update this page with the list of new items for the next release as they are worked
In the next release: (Bolded items are new and NOT in the v2.0 alpha)
New normalization bandpasses: johnson_u, johnson_b, johnson_r, cousins_r, galex_fuv, galex_nuv. None of the new normalization bandpasses are within the wavelength range of JWST.
The engine can now specify all the same hst_calspec spectra as the HST ETC, though many do not cover redward of 1 micron. The new list is agk81d266, bd+17d4708, bd+28d4211, bd+75d325, feige34, feige110, gd50, gd71, gd108, gd153, grw+70d5824, g191b2b, hz21, hz43, hz44, lb227, lds749b, ngc7293, p330e, solar, sirius, vb8, vega, wd0308-565, wd0947+857, wd1057+719, wd1657+343.
The lower wavelength limit has been changed to 0.09 microns (900 Angstroms), which allows these spectra to be normalized with bluer filters (e.g. Johnson V) even when redshifted.
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What support is available?
Questions about the Pandeia engine for Webb may be directed to the JWST help desk; for Roman, email help@stsci.edu with Roman and/or WFIRST in the subject line or body. However, due to the complexity of the engine, support will be limited and response times may be longer than for other tools.
We welcome comments and feature requests, and these will be considered along with other ETC work.
What is the Pandeia Engine?
The Pandeia engine uses a pixel-based 3-dimensional approach to perform calculations on small (typically a few arcseconds) 2-dimensional user-created astronomical scenes. It models both the spatial and the wavelength dimensions, using realistic point spread functions (produced using WebbPSF) for each instrument mode. It natively handles correlated read noise, inter-pixel capacitance, and saturation. Since the signal and noise are modeled for individual detector pixels, the ETC is able to replicate many of the steps that observers will perform when calibrating and reducing their JWST data. This simplifies interpretation of the extracted signal-to-noise ratio (SNR) calculated by the ETC.
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While the Pandeia engine includes many effects not typically included in other ETCs, it is not an observation simulator. It does not simulate the full detector, nor does it include 2-dimensional effects such as distortion. |
Details on the algorithms used to compute signal and noise on the detector and the strategies used to compute the extracted products can be found in Pontoppidan et al. 2016.