IRAC Calibration
Goals: 10% absolute, 2% relative calibration accuracy
Flat fields and Dark frames
- Shutter and internal calibration sources - measure internal IRAC flat, monitor pixel-to-pixel gain differences
- Sky Flats - needed to determine full system flat over FOVs
Flux calibration
- Ground-based measurements
- System responsivity as a function of wavelength - in-band and out-of-band
- Absolute calibration estimate
- standard stars - measured spectra and models, absolute calibration
- In-orbit standard star measurements
- range of fluxes, colors
- compare to other ground- and space-based measurements
calibration observations repeated (hourly, 12h, weekly) to monitor changes in instrument responsivity