Exposure Time Calculators

Roman Coronagraph Exposure Time Calculator

The Roman Coronagraph Exposure Time Calculator (ETC) is the public version of the exposure time calculator of the Coronagraph Instrument aboard the Nancy Grace Roman Space Telescope. The "Roman Coronagraph ETC" allows the user to derive integration times for self-luminous exoplanets, reflected light exoplanets, circumstellar disks, and polarized targets for each coronagraph observing mode, and in two performance scenarios: "optimistic" and "conservative". The SNR, integration times, and best observing epochs are computed taking into account accessible periods from the observatory. For more information, see a talk from the Coronagraph Information Session. Also, this Deep Dive session demonstrates the ETC, including a review of the available observing modes and performance scenarios, the input parameters for each target type, how the results are stored and read, and a summary of its current limitations. Installation instructions and documentation for the ETC are available at GitHub.

Roman Space Telescope Galaxy Survey Exposure Time Calculator

The Roman Space Telescope Galaxy Survey Exposure Time Calculator is Chris Hirata's exposure time calculator for use in optimizing hardware requirements and observing strategy for the Roman Space Telescope High Latitude Survey (HLS). It takes known galaxy properties to predict the limiting magnitudes and statistical properties of sources that can be detected by Roman Space Telescope for gravitational weak lensing and the galaxy redshift survey. It also has modes to help with the photo-z calibration emission line sensitivities and with estimating the spectral continuum sensitivity. The current update (version 17) of this code incorporates new options for the BAO survey ([O II] and [O III] lines) and Fowler-4/Fowler-8 readout options. Four configuration files are now available, including the WFI direct imaging blue and red wavelengths, and the WFI grism and prism modes.

Roman Space Telescope Pandeia: A Multi-mission Exposure Time Calculator

Pandeia, named for the Greek goddess of brightness, is a multi-mission exposure time calculator built at STScI to support JWST. Pandeia calculates a detailed and accurate system performance for a wide variety of science cases and includes support for direct imaging, slitless spectroscopy, IFC spectroscopy, and coronagraphy. It is not limited to calculations of a single source, and includes the ability to build complex astronomical scenes. STScI has extended Pandeia to support the Roman Space Telescope. It implements the current Roman Space Telescope optical reference information. Download instructions, tutorial notebooks, and references are available through a GitHub repository. Users are encouraged to address questions, suggestions, and bug reports to help@stsci.edu with "Pandeia-Roman question" in the subject line. The message will be directed to the appropriate members of the Pandeia-Roman team at STScI.