Background

How much background (in counts/sec) to subtract before calibration.

Usage

Source

Background(
    mode="none",
    rtg_value=0.0004,
    spatial_bin=1,
    spectral_bin=1,
    wavelength_range=None
)

Models the two IDL background modes as data instead of flags:

  • "none" — subtract nothing (default).
  • "rtg" — subtract a constant dark rate rtg_value (the radioisotope-thermoelectric-generator background, IDL pass.rtg).
  • "spectral_average" — estimate the background from a featureless wavelength band (wavelength_range) by averaging counts/sec over the spectral axis, then subtract that per-(slit, readout) average from every spectral sample.

spatial_bin/spectral_bin are carried for parity with the IDL spec but are not yet used by the stand-in spectral-average estimator.

Parameter Attributes

mode: str = "none"
rtg_value: float = 0.0004
spatial_bin: int = 1
spectral_bin: int = 1
wavelength_range: tuple[float, float] | None = None

Methods

Name Description
offset() Return the amount to subtract from counts_per_sec.

offset()

Return the amount to subtract from counts_per_sec.

Usage

Source

offset(counts_per_sec, wavelength)

counts_per_sec is the (NX, NY, NZ) cube already divided by the integration time; wavelength is the (NX,) centre-wavelength axis. The return value is a scalar (none/rtg) or a (1, NY, NZ) array (spectral_average) — both broadcast cleanly against the cube.