Diffphot is a Python package for differential photometry of time-series data. The package can be used as a fully automated data reduction pipeline or can be used as a interactive data reduction tool in a iPython or Notebook interface.
Diffphot can do following tasks in automated or interactive modes:
- Finding best image as template based on image quality.
- Finding co-ordinate transformation relations among image frames for cross-identifying stars or aligning images.
- Automatically determine parameters or other image information - like readnoise, gain, filter, Julian date - using a telescope database.
- Doing aperture or PSF photometry.
- Multi-threaded photometry can be done, where multiple images are processed parallelly.
- Then perform relative calibration of image frames for differential photometry.
- Optionally Astrometry can be also done if needed.
- Standard calibration can be done using SDSS, PanSTARRS, 2MASS or APASS catalog as needed
- Interactive mode - functions are provided for Displaying images with target and field stars labeled along with aperture and sky annuls drawn.
- Interactive mode - functions for plotting light curves and showing data tables at various stages of reductions. Photometric uncertainties, relative calibration uncertainties and standard calibration uncertainties are also listed individually.
- In interactive mode, problematic images can be investigated individually, parameters can be tweak as needed and then photometry steps can be re-run for the particular frame.
Diffphot has lot of advanced functionality and is highly configureable. A detailed documentation of this package is currently not available but will be done in future.