optixstuff.disperser

Disperser hardware descriptors for integral field spectrographs.

optixstuff owns the descriptor: the interface plus a cheap closed-form scalar/ETC face. The heavy render logic (building the forward operator) lives in coronachrome. This mirrors the coronagraph split, so jaxedith and yield tools can read IFS hardware info without importing the render engine.

Classes

AbstractDisperser	Interface for a dispersing IFS element (lenslet array, slicer, MSA).
LensletDisperser	Lenslet-array IFS disperser (CRISPY heritage).

Functions

_polyval_deriv(coeffs, x)

Evaluate the derivative of a descending-order polynomial at x.

Module Contents

class optixstuff.disperser.AbstractDisperser

Bases: equinox.Module

Interface for a dispersing IFS element (lenslet array, slicer, MSA).

Only the scalar/ETC face is defined here. Render geometry lives in coronachrome and dispatches on the concrete descriptor type.

abstractmethod spectral_resolution(wavelength_nm)

Resolving power R = lambda / dlambda at the given wavelength.

abstractmethod spectral_sampling()

Detector pixels per resolution element.

abstractmethod n_pix_spread(wavelength_min_nm, wavelength_max_nm)

Detector pixels a single spaxel spectrum spans across a band.

abstractmethod throughput(wavelength_nm)

Disperser optical throughput in [0, 1] at the given wavelength.

optixstuff.disperser._polyval_deriv(coeffs, x)

Evaluate the derivative of a descending-order polynomial at x.

class optixstuff.disperser.LensletDisperser

Bases: AbstractDisperser

Lenslet-array IFS disperser (CRISPY heritage).

Config only. The render geometry (IR build) is performed by coronachrome, which reads these fields. Scalar/ETC methods derive from dispersion_coeffs + pix_per_reselt so the dispersion model is the single source of truth.

psflet_params[0] is the PSFlet core width in detector pixels (Gaussian sigma or Moffat alpha); any trailing entries are dimensionless shape parameters (e.g. Moffat beta). psflet_ref_nm is the wavelength at which that core width is specified: a diffraction-limited spot scales as lambda f / D, so at fixed pixel scale coronachrome scales the core width by lambda / psflet_ref_nm per wavelength (the shape parameters do not scale).

sky_pitch_arcsec is the lenslet pitch projected on sky, a plain angle in arcseconds (the focal-plane cube a render layer consumes lives on a fixed angular grid, so no reference wavelength is involved). It makes the spatial sampling an instrument property: the render layer derives focal-plane pixels per lenslet as the ratio of this pitch to the cube’s angular plate scale instead of taking a free knob. None means unspecified.

psflet_pack_path is a reference to a frozen PSFlet template pack file (used with psflet_kind="template"), the way throughput_element carries the blaze curve: config only, the render layer loads it.

pitch_m: float

pixsize_m: float

angle_rad: float

lam_ref_nm: float

pix_per_reselt: float

dispersion_coeffs: jax.Array

psflet_params: jax.Array

psflet_ref_nm: float

grid_kind: str

n_lenslets: int

psflet_kind: str

detector_shape: tuple[int, int]

throughput_element: optixstuff.optical_elements.AbstractOpticalElement

sky_pitch_arcsec: float | None = None

psflet_pack_path: str | None

_dispersion_px(wavelength_nm)

Spectral-axis detector offset [px] for the wavelength(s).

spectral_resolution(wavelength_nm)

R = (local px per unit log-lambda) / pixels-per-resolution-element.

spectral_sampling()

Detector pixels per resolution element.

n_pix_spread(wavelength_min_nm, wavelength_max_nm)

Spectral trace length [px] across a band, plus a PSFlet-width margin.

throughput(wavelength_nm)

Disperser optical throughput in [0, 1], shaped like wavelength_nm.

Delegates to the composed throughput element (ConstantThroughput by default; SpectralThroughput for a tabulated blaze/transmission curve) and broadcasts to the wavelength shape so the output shape is canonical regardless of the backing element.