MIRI Target Acquisition
The JWST Mid-Infrared Instrument (MIRI) provides target acquisition capabilities for the low-resolution spectroscopy, medium-resolution spectroscopy, and coronagraphic imaging modes.
Target acquisition (TA) is a procedure that centroids a source and places it accurately within an aperture, region of interest (ROI), or subarray. The filters available for MIRI TA are F560W, F1000W, F1500W, and FND. TA procedures are discussed in the context of the observatory in memos and reports by Gordon & Meixner (2008), Meixner et al. (2006), Nelan et al. (2005), and Meixner et al. (2004).
TA procedures in the Astronomer's Proposal Tool (APT) are available in these articles:
- MIRI LRS Slit Target Acquisition
- MIRI LRS Slitless Target Acquisition
- MIRI MRS Target Acquisition
- MIRI Coronagraphic Imaging Target Acquisition
MIRI Target Acquisition Readout Patterns.
See also: Understanding Exposure Times
Words in bold italics are buttons
or parameters in GUI tools. Bold
style represents GUI menus/
panels & data software packages.
The FAST readout mode and the FASTGRPAVG series of readout modes are available for MIRI target acquisition only. The FASSTGRPAVG readout modes allow for longer exposure times. This is done by averaging a given number of MIRI frames together in the ISIM FPAP (Focal Plane Array Processor) as a group. Note that all MIRI target acquisition exposures use one integration.
(as offered in APT)
Number of averaged MIRI frames
|Group Time |
|FAST||1||2.775 s||0.159 s||0.324 s||0.24 s|
|FASTGRPAVG||4||11.10 s||0.64 s||1.30 s||0.96 s|
|FASTGRPAVG8||8||22.20 s||1.27 s||2.59 s||1.92 s|
|FASTGRPAVG16||16||44.40 s||2.54 s||5.18 s||3.84 s|
|FASTGRPAVG32||32||88.80 s||5.09 s||10.37 s||7.67 s|
|FASTGRPAVG64||64||177.60 s||10.18 s||20.74 s||15.34 s|
Mid-InfraRed Instrument (MIRI) Target Acquisition Strategies and Use Cases
Gordon, K., 2008, JWST-STScI-001347 (PDF)
Mid-Infrared Instrument (MIRI) Low Resolution Target Acquisition for Faint Sources
Meixner, M. et al., 2004, STScI-JWST-TM-2004-0018A
Mid-Infrared Instrument (MIRI) Target Acquisition Requirements and Strategies
Nelan, E. et al., 2005, STScI-JWST-R-2005-0001
JWST Science Instrument Target Acquisition Concepts