MIRI MRS TSOs
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.
On this page
Sensitivity and saturation
See also: MIRI Performance, MIRI Sensitivity, MIRI Bright Source Limits
The sensitivity and saturation of the MRS is the same for TSOs as for regular observations.
Dithering
See also: MIRI Dithering, MIRI MRS APT Template
Words in bold are GUI menus/
panels or data software packages;
bold italics are buttons in GUI
tools or package parameters.
Target acquisition
See also: MIRI MRS Target Acquisition, JWST 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.
The total number of groups in a single exposure, summed over all integrations, is limited to 196,608 due to onboard storage restrictions; in addition the maximum number of integrations per exposure is 65,535. Many TSOs therefore require multiple exposures to cover the full desired duration. For TSOs with MRS, data volume constraints are usually the limiting factor for exposure duration rather than on-board storage issues.
MRS TSOs in APT
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.