_ (Software for Calibrating AstroMetry and Photometry) is a computer program that computes astrometric projection parameters from source catalogues derived from _ images. The computed solution is expressed according to the _ standard. The main features of are:
- Compatibility with _ or Multi-Extension catalogue format in input,
- Generation of -compliant and _-compatible FITS image headers in output,
- Automatic grouping of catalogues on the sky
- Selectable on-line astrometric reference catalogue
- Automatic determination of scale, position angle, flipping and coordinate shift using fast pattern-matching
- Various astrometric calibration modes for single detectors and detector arrays
- Combined astrometric solutions for multi-channel/instrument surveys
- Highly configurable astrometric distortion polynomials
- Correction for differential chromatic refraction
- Proper motion measurements
- Multi-threaded code that takes advantage of multiple processors.
- _-compliant _ output of meta-data.
- _ filter sheet provided for convenient access to metadata from a regular web browser.