JWST Slit Spectroscopy Roadmap
Words in bold are GUI menus/
panels or data software packages;
bold italics are buttons in GUI
tools or package parameters.
Each step listed below is followed by a list of articles with additional details.
- Choose which instrument you wish to use, based on the wavelength range of interest. Roughly, 5 μm is the boundary between NIRSpec and MIRI.
- Choose your method of target acquisition.
NIRSpec Target Acquisition - NIRSpec has 3 options. In brief, None is not recommended, and WATA will generally suffice.
MIRI LRS Slit Target Acquisition - TA is recommended for the LRS slit.
- Decide if a mosaic or a single slit pointing is desired. See the detailed mosaic guides for more information
NIRSpec FS and IFU Mosaic APT Guide
MIRI LRS Mosaics
- Decide on the slit(s), subarray(s), grating(s), and filter(s).
NIRSpec Dispersers and Filters - NIRSpec provides many options.
For MIRI, you should choose FULL subarray in the APT to ensure that you observe in the slit. If a spectral resolving power greater than 200 is desired, then the MRS may be a better choice.
- Choose a dither pattern.
NIRSpec FS Dither and Nod Patterns - NIRSpec offers many patterns.
MIRI LRS Dithering - If observing a more extended source, 2 options are available. The user can either create a dedicated background (which is the preferred method) or use the MAPPING dither pattern. See MIRI LRS Recommended Strategies for further guidance on background observations.
- Calculate exposure times, both for TA and for science observation, using the Exposure Time Calculator (ETC). Both NIRSpec and MIRI provide a great deal more information on readout modes:
NIRSpec Detector Readout Modes and Patterns
MIRI Detector Readout Overview
- Create an APT file. Step-by-step instructions are available for both NIRSpec and the MIRI LRS:
NIRSpec Fixed Slit Spectroscopy APT Template
MIRI LRS APT Template
For questions about the APT not covered by the 2 links above, see the JWST APT Overview.
Go to the Getting Started with JWST Proposing to complete the steps for proposal submission.