satsim.background package

Background component helpers.

satsim.background.apply_background_stray_augmentation(components, pre_cloud_pe): Return components updated after legacy stray-background augmentation.

satsim.background.background_components_from_config(ssp, zeropoint, pixel_area_arcsec2, exposure_s)

Build static pre-cloud background PE components from ssp['background'].

Returned component values are in photoelectrons per pixel per exposure. Static components include galactic sky, artificial skyglow residual, and legacy stray light. Frame-dependent Sun and Moon terms are added by background_frame_components_from_config().

satsim.background.background_frame_components_from_config(ssp, zeropoint, pixel_area_arcsec2, exposure_s, observer, site_mode, astrometrics, ts_mid)

Build frame-dependent background PE components from Sun/Moon geometry.

The returned dictionary has components, active, and metadata entries matching the static component structure. astrometrics must contain the current frame boresight fields used for angular separation.

satsim.background.background_modes(background): Resolve configured moon, twilight, and daytime modes to concrete models.

satsim.background.hosek_wilkie_daytime_component(ssp, observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the Hosek-Wilkie daytime PE residual and diagnostic metadata.

satsim.background.hosek_wilkie_daytime_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Hosek-Wilkie daytime brightness in mag/arcsec^2.

satsim.background.hosek_wilkie_transition_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Hosek-Wilkie brightness with a twilight-to-daytime horizon blend.

satsim.background.krisciunas_schaefer_moon_brightness_nl(phase_angle_deg, moon_sky_separation_deg, moon_zenith_deg, target_zenith_deg, extinction=0.172): Return the K&S scattered moonlight contribution in nanoLamberts.

satsim.background.krisciunas_schaefer_moon_component(observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the K&S moonlight PE contribution and diagnostic metadata.

satsim.background.luminance_to_surface_brightness(luminance_cd_m2): Convert V-like photopic luminance to mag/arcsec^2.

satsim.background.nano_lamberts_to_surface_brightness(nano_lamberts): Convert V-band sky brightness from nanoLamberts to mag/arcsec^2.

satsim.background.patat_twilight_component(ssp, observer, ts_mid, zeropoint, pixel_area_arcsec2, exposure_s): Return the Patat twilight PE residual and diagnostic metadata.

satsim.background.patat_twilight_surface_brightness(sun_zenith_deg): Return Patat V-band zenith twilight brightness in mag/arcsec^2.

satsim.background.perez_daytime_component(ssp, observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the Perez daytime PE residual and diagnostic metadata.

satsim.background.perez_daytime_relative_luminance(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Perez/CIE relative luminance for a target sky direction.

satsim.background.perez_daytime_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return fixed-normalization Perez daytime brightness in mag/arcsec^2.

satsim.background.surface_brightness_residual_pe(zeropoint, brightness, baseline_brightness, pixel_area_arcsec2, exposure_s): Return the positive PE residual between two surface-brightness levels.

satsim.background.surface_brightness_to_luminance(brightness): Convert V-like mag/arcsec^2 to luminance in cd/m^2.

satsim.background.surface_brightness_to_pe(zeropoint, brightness, pixel_area_arcsec2, exposure_s): Convert visual magnitude per arcsec^2 to PE per pixel per exposure.

Submodules

satsim.background.components module

Background component assembly and config mode dispatch.

satsim.background.components.apply_background_stray_augmentation(components, pre_cloud_pe): Return components updated after legacy stray-background augmentation.

satsim.background.components.background_components_from_config(ssp, zeropoint, pixel_area_arcsec2, exposure_s)

Build static pre-cloud background PE components from ssp['background'].

Returned component values are in photoelectrons per pixel per exposure. Static components include galactic sky, artificial skyglow residual, and legacy stray light. Frame-dependent Sun and Moon terms are added by background_frame_components_from_config().

satsim.background.components.background_frame_components_from_config(ssp, zeropoint, pixel_area_arcsec2, exposure_s, observer, site_mode, astrometrics, ts_mid)

Build frame-dependent background PE components from Sun/Moon geometry.

The returned dictionary has components, active, and metadata entries matching the static component structure. astrometrics must contain the current frame boresight fields used for angular separation.

satsim.background.components.background_modes(background): Resolve configured moon, twilight, and daytime modes to concrete models.

satsim.background.daytime module

Daytime background models.

satsim.background.daytime.hosek_wilkie_daytime_component(ssp, observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the Hosek-Wilkie daytime PE residual and diagnostic metadata.

satsim.background.daytime.hosek_wilkie_daytime_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Hosek-Wilkie daytime brightness in mag/arcsec^2.

satsim.background.daytime.hosek_wilkie_transition_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Hosek-Wilkie brightness with a twilight-to-daytime horizon blend.

satsim.background.daytime.perez_daytime_component(ssp, observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the Perez daytime PE residual and diagnostic metadata.

satsim.background.daytime.perez_daytime_relative_luminance(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return Perez/CIE relative luminance for a target sky direction.

satsim.background.daytime.perez_daytime_surface_brightness(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg): Return fixed-normalization Perez daytime brightness in mag/arcsec^2.

satsim.background.hosek_wilkie module

Hosek-Wilkie CIE Y-channel clear-sky evaluator.

satsim.background.hosek_wilkie.default_ground_albedo(): Return the default Hosek-Wilkie ground albedo.

satsim.background.hosek_wilkie.default_turbidity(): Return the default Hosek-Wilkie atmospheric turbidity.

satsim.background.hosek_wilkie.hosek_wilkie_luminance(target_zenith_deg, sun_zenith_deg, sun_sky_separation_deg, turbidity=3.0, ground_albedo=0.1): Return Hosek-Wilkie CIE Y-channel sky luminance in cd/m^2.

satsim.background.moon module

Lunar background models.

satsim.background.moon.krisciunas_schaefer_moon_brightness_nl(phase_angle_deg, moon_sky_separation_deg, moon_zenith_deg, target_zenith_deg, extinction=0.172): Return the K&S scattered moonlight contribution in nanoLamberts.

satsim.background.moon.krisciunas_schaefer_moon_component(observer, ts_mid, ra_deg, dec_deg, target_el_deg, zeropoint, pixel_area_arcsec2, exposure_s): Return the K&S moonlight PE contribution and diagnostic metadata.

satsim.background.twilight module

Twilight background models.

satsim.background.twilight.patat_twilight_component(ssp, observer, ts_mid, zeropoint, pixel_area_arcsec2, exposure_s): Return the Patat twilight PE residual and diagnostic metadata.

satsim.background.twilight.patat_twilight_surface_brightness(sun_zenith_deg): Return Patat V-band zenith twilight brightness in mag/arcsec^2.

satsim.background.units module

Background unit conversions.

satsim.background.units.luminance_to_surface_brightness(luminance_cd_m2): Convert V-like photopic luminance to mag/arcsec^2.

satsim.background.units.nano_lamberts_to_surface_brightness(nano_lamberts): Convert V-band sky brightness from nanoLamberts to mag/arcsec^2.

satsim.background.units.surface_brightness_residual_pe(zeropoint, brightness, baseline_brightness, pixel_area_arcsec2, exposure_s): Return the positive PE residual between two surface-brightness levels.

satsim.background.units.surface_brightness_to_luminance(brightness): Convert V-like mag/arcsec^2 to luminance in cd/m^2.

satsim.background.units.surface_brightness_to_pe(zeropoint, brightness, pixel_area_arcsec2, exposure_s): Convert visual magnitude per arcsec^2 to PE per pixel per exposure.