The MIRI medium-resolution spectrometer can be used for time-series observations (TSOs). Please see the MIRI MRS main article for top-level information about the mode and its operation.

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Sensitivity and saturation

See also: MIRI PerformanceMIRI SensitivityMIRI Bright Source Limits

The sensitivity and saturation of the MRS is the same for TSOs as for regular observations. 


See also: MIRI DitheringMIRI MRS APT Template

Words in bold are GUI menus/
panels or data software packages; 
bold italics are buttons in GUI
tools or package parameters.

No dithering is allowed for TSOs. Selecting the Time Series Observations special requirement in the Astronomer's Proposal Tool (APT) will disable dithering options.

Target acquisition

See also: MIRI MRS Target AcquisitionJWST Pointing Performance

Target acquisition (TA) is supported for TSOs with the MRS. Without TA, the accuracy of the target placement in the MRS field is determined by the telescope's blind pointing accuracy

Exposure time limitations

See also: JWST Time-Series Observations Roadmap

It is recommended that TSOs are carried out in a single exposure. Regular observations have an exposure time limit of 10,000 s for a single exposure. For TSOs, this limitation is waived for optimal stability and spectrophotometric precision. Selecting Time Series Observation in the Special Requirements pane in APT enables this waiver. 


See also: JWST Time-Series Observations Roadmap

An MRS time-series observation can be prepared in APT with the medium-resolution spectroscopy template, by selecting the Time Series Observation special requirement. The No Parallel requirement is mandatory for TSOs as well. 

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