wcc-etc: Exposure Time Calculator for the Lazuli WCC

wcc-etc is the exposure time calculator (ETC) for the Wide-field Context Camera (WCC) on Lazuli, the flagship instrument of the Schmidt Observatory System. It models a sky scene, propagates it through a telescope and sensor, and returns photometric signal-to-noise ratios, required exposure times, simulated detector images, saturation flags, and ready-made diagnostic plots.

A hosted web version of the ETC is available at simulators.schmidtobservatorysystem.org/wcc.

Note

New here? Read Installation and then work through Quick start. The Tutorials are runnable Jupyter notebooks that cover every major feature end to end.

Highlights

• Scene model — stellar/galaxy templates or parametric source spectra (blackbody, flat \(F_\nu\)/\(F_\lambda\), power law, emission lines), optional host galaxy, and a sky background (zodiacal light, moon scatter).

• Signal-to-noise — analytic Airy approximation and a PSF-aware, image-based SNR with circular-aperture photometry and aperture optimization.

• Exposure-time inversion — solve for the exposure time that reaches a target SNR, with multi-read (n_reads) support.

• PSF & image simulation — diffraction-limited Airy PSFs, bundled Zemax defocus PSFs, custom PSFs, telescope jitter, Poisson + read noise, and per-pixel saturation masks.

• Plotting — matplotlib and bokeh helpers for images, radial profiles, and encircled-energy curves, plus a shared house style.

Contents

Getting started

• Installation
  • Requirements
  • Install from source (recommended)
  • Using a conda environment
  • Verify the installation
  • Running the test suite
  • Building the documentation locally
• Quick start
  • The mental model
  • 1. Build a scene
  • 2. Create a simulation for a sensor
  • 3. Compute signal-to-noise
  • 4. Invert: exposure time for a target SNR
  • 5. Change parameters and recompute
  • 6. Check saturation
  • 7. Simulate a detector image and plot it
  • Where to go next

User guide

• User guide
  • Concepts and architecture
  • Scenes, sources, and backgrounds
  • Signal-to-noise and exposure time
  • PSFs and image simulation
  • Saturation
  • Plotting

Tutorials

• Tutorials

Reference

• API reference
  • Top-level public API
  • Modules
• Configuration and sensors
  • Sensor strings
  • The configuration files
  • Example — the Sony detector config
  • Example — the telescope config
  • Overriding configuration at runtime
  • Reading configs programmatically
• Changelog
  • v0.1.0

Indices and tables

• Index

• Module Index

• Search Page