simtools-derive-incident-angle#

Derive photon incident angles on focal plane and primary/secondary mirrors.

Save model-parameter tables, per-offset angle histograms, metadata and logs. Simulation model assets and scripts are removed after successful completion. Use --keep_photon_files to retain raw photon lists, and --debug_plots to save plots.

Creates photon files with additional columns for incident angles calculation. Outputs files and histograms of the incidence angles at the focal plane, primary mirror, and if available, secondary mirror. Optional debug plots can be also generated.

Note that this application does not include a full raytracing of telescope structures, and their non-symmetric shadowing at off-axis angles.

Example of a focal-plane incident angle plot for a SST:

../../_images/incident_angles_multi_derive_incident_angle_SSTS-04.png

Example of a primary mirror incident angle plot for a SST:

../../_images/incident_angles_primary_multi_derive_incident_angle_SSTS-04.png

Note also the relation between radius and primary mirror incident angles, and how this relates to: the peak seen in the primary mirror incident angle distribution:

../../_images/primary_angle_vs_radius.png

Example of a secondary mirror incident angle plot for a SST:

../../_images/incident_angles_secondary_multi_derive_incident_angle_SSTS-04.png

Command line arguments#

options#

–help: show this help message and exit
–keep_photon_files: Keep the raw ray tracing photon lists in the output directory
–perfect_mirror: Assume perfect mirror shape/alignment/reflection
–debug_plots: Save angle plots and debug plots

application#

–zenith_angle

Zenith angle in degrees (between 0 and 180).

–off_axis_angles

One or more off-axis angles in degrees (unitless values are interpreted as degrees).

Default: [<Quantity 0. deg>].

–source_distance

Source distance in km (unitless values are interpreted as km).

Default: 10.0 km.

–number_of_photons

Number of star photons to trace (per run).

Default: 10000.

–show_options

Print available values for a supported option and exit.

ray tracing configuration#

–ray_tracing_backend

Optical ray-tracing backend (default: sim_telarray).

Choices: sim_telarray, obdeect.

simulation configuration#

–instrument_seed: Seed of the random instrument setup (e.g. mirror deviations, gains); with several random instrument instances, their seeds are derived from it (default: random).
–simulation_seed: Seed of the simulation (events, photons) (default: random). Two values: [instrument_seed, simulation_seed] (use for testing only).

simulation model#

–model_version: Simulation production model version(s). Use –show_options model_version.
–parameter_version: model parameter version
–overwrite_model_parameters: JSON string with model parameters to overwrite
–site: Observatory site (e.g., North, South). Use –show_options site.
–telescope: telescope model name (e.g., LSTN-01, SSTS-design, …)

model repository#

–simulation_models_path: Path containing the simulation-model repository to read.
–simulation_models_git_path: Path to a local normal, bare, or mirror Git repository containing simulation models.
–simulation_models_git_revision: Git tag, ref, or commit to read from the simulation-model repository.

Examples#

Derive photon incidence angles for an SST#

Ray-trace an off-axis source through a dual-mirror SST and derive camera photon-incidence angles. Tests export of all three incidence-angle model parameters for dual-mirror telescopes.

Application: simtools-derive-incident-angle

Integration test: derive_incident_angle_run_dual_mirror.yml

Command

simtools-derive-incident-angle --config tests/integration_tests/config/derive_incident_angle_run_dual_mirror.yml

Configuration

site: South
telescope: SSTS-01
off_axis_angles: 1.0
number_of_photons: 10000
model_version: 6.0.2
output_path: simtools-output
parameter_version: 1.0.0

Inspect dual-mirror photon incidence angles with debug plots#

Ray-trace an SST and plot photon incidence on its primary, secondary, and camera surfaces with additional debug plots enabled.

Application: simtools-derive-incident-angle

Integration test: derive_incident_angle_run_dual_mirror_debug.yml

Command

simtools-derive-incident-angle --config tests/integration_tests/config/derive_incident_angle_run_dual_mirror_debug.yml

Configuration

site: South
telescope: SSTS-01
off_axis_angles: 1.0
number_of_photons: 1000
model_version: 6.0.2
output_path: simtools-output
debug_plots: true
parameter_version: 1.0.0

Derive photon incidence angles for an LST#

Ray-trace an off-axis source through a single-mirror LST and derive camera photon-incidence angles. Tests export of the filter incidence distribution for single-mirror telescopes.

Application: simtools-derive-incident-angle

Integration test: derive_incident_angle_run_single_mirror.yml

Command

simtools-derive-incident-angle --config tests/integration_tests/config/derive_incident_angle_run_single_mirror.yml

Configuration

site: South
telescope: LSTS-04
off_axis_angles: 1.0
number_of_photons: 10000
model_version: 6.0.2
output_path: simtools-output
parameter_version: 1.0.0