NIRISS SOSS planning tool

As its name suggests, the Single-Object Slit-less Spectroscopy (SOSS) mode of NIRISS is slit-less and thus the spectrum of a target star may be contaminated by partly overlapping spectra of nearby stars. For a given target, the details of this potential contamination are a function of the Aperture Position Angle (APA) at which the observations are taken. This tool simulates SOSS observations of a given target and produces an estimate of the level of contamination as a function of the APA of the observation; it may be used to plan observations at the optimal APA. The tool also computes the JWST accessibility windows of the target, along with the corresponding accessible PAs for NIRISS observations.

Usage notes:

Input information

Target name:
Coordinates: RA (HH:MM:SS.S) DEC (DDD:MM:SS.S)
Apply target proper motion using information below:
     pm in RA (mas/yr), pm in DEC (mas/yr), Julian epoch of RA/DEC given above [comma separated]
Add a close binary companion not present in 2MASS, using information below:
     RA offset ("), DEC offset ("), 2MASS J (mag), H (mag) and Ks (mag) [comma separated]


(Be patient, this may take up to one minute...)
(This is quick, about 2 seconds.)