Overview

The signal-to-noise ratio for a given target (point or extended), observing configuration, and required exposure time are computed by this tool. Three values of the signal-to-noise ratio are returned: worst case (minimum), best case (maximum) , and typical (median), as determined over the course of a single orbit.


Input Data Specifications

Spacecraft/Telescope Architecture (ARCH)

Nominal JWST orbit -- large L2 Lissajous (2012.092 to 2027.124; 15-yr duration)
Alternative JWST orbit -- worst-case stray-light orbit (2011.254 to 2021.219; 10-yr duration)
Other: * See Note.

Integrated Science Instrument Module (ISIM)

JWST Requirements
JWST Goals
Other: * See Note.

Observation Parameters

Target
Coordinates , degrees
Coord. System
Diameter (arcsec)
AB Mag

Exposure Mode
Single Exposure Mode
Survey Mode (Enter target density and number required below)
Density (#/arcmin^2)
Number required

SI Configuration
Sci Instrument
Num. of positions
in dither pattern
Wavelength microns
Spectral
Resolution
Aperture
Photometry
pixels
Exposure Time hours

*Note: User-supplied filenames should have a .txt extension.


Processing and Reporting Options

 Run in batch mode.
 Report input data as well as results.

The results are based on a data set consisting of values calculated at equally spaced points around an orbit. For each observation, the following report options are available:

 Display the median data set value
 Display the minimum, median and maximum data set values
 Display the minimum and maximum data set values
 Display the entire data set (all time points -- only applicable with single-visit input)

Stray Light model: - for the OTA, sunshield, and background sources. NOTE that the finite-element model may take several hours to complete with the full DRM.
Comment string: (will be included in output file)



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