NIRCam¶
- class webbpsf.NIRCam[source]¶
Bases:
JWInstrument
A class modeling the optics of NIRCam.
Relevant attributes include
filter
,image_mask
, andpupil_mask
.The NIRCam class is smart enough to automatically select the appropriate pixel scale for the short or long wavelength channel based on the selected detector (NRCA1 vs NRCA5, etc), and also on whether you request a short or long wavelength filter. The auto-selection based on filter name can be disabled, if necessary, by setting
auto_channel = False
. Setting the detector name always toggles the channel regardless ofauto_channel
.Note, if you use the
monochromatic
option for calculating PSFs, that does not invoke the automatic channel selection. Make sure to set the correct channel prior to calculating any monochromatic PSFs.Similarly, SIAF aperture names are automatically chosen based on detector, filter, image mask, and pupil mask settings. The auto-selection can be disabled by setting
auto_aperturename = False
. SIAF aperture information is mainly used for coordinate transformations between detector science pixels and telescope V2/V3.Special Options: The ‘bar_offset’ option allows specification of an offset position along one of the coronagraph bar occulters, in arcseconds.
` nc.image_mask = 'MASKLWB' nc.options['bar_offset'] = 3 # 3 arcseconds towards the right (narrow end on module A) `
Similarly, the ‘coron_shift_x’ and ‘coron_shift_y’ options will offset the mask in order to produce PSFs centered in the output image, rather than offsetting the PSF. This is useful for direct PSF convolutions of an image. Values are in arcsec. These options move the mask in the opposite sense as nc.options[‘bar_offset’].
` nc.options['coron_shift_x'] = 3 # Shifts mask 3" to right, equivalent to source 3" to left. `
The ‘nd_squares’ option allows toggling on and off the ND squares for TA in the simulation. Note that these of course aren’t removable in the real instrument; this option exists solely for some simulation purposes.
Attributes Summary
SIAF aperture name for detector pixel to sky coords transformations
Detector selected for simulated PSF
Currently selected filter name (e.g.
Currently selected image plane mask, or None for direct imaging
Currently selected Lyot pupil mask, or None for direct imaging
Attributes Documentation
- LONG_WAVELENGTH_MAX = 5.299999999999999e-06¶
- LONG_WAVELENGTH_MIN = 2.35e-06¶
- SHORT_WAVELENGTH_MAX = 2.35e-06¶
- SHORT_WAVELENGTH_MIN = 6e-07¶
- aperturename¶
SIAF aperture name for detector pixel to sky coords transformations
- channel¶
- detector¶
Detector selected for simulated PSF
Used in calculation of field-dependent aberrations. Must be selected from detectors in the
detector_list
attribute.
- filter¶
Currently selected filter name (e.g. F200W)
- image_mask¶
Currently selected image plane mask, or None for direct imaging
- module¶
- pupil_mask¶
Currently selected Lyot pupil mask, or None for direct imaging