MegaPipe: The MegaCam image stacking pipeline at the Canadian astronomical data centre

This paper describes the MegaPipe image processing pipeline at the Canadian Astronomical Data Centre. The pipeline combines multiple images from the MegaCam mosaic camera on Canada-France-Hawaii Telescope (CFHT) and combines them into a single output image. MegaPipe takes as input detrended MegaCam images and does a careful astrometric and photometric calibration on them. The calibrated images are then resampled and combined into image stacks. The astrometric calibration of the output images is accurate to within 0.15 relative to external reference frames and 0.04 internally. The photometric calibration is good to within 0.03 mag. The stacked images and catalogs derived from these images are available through the CADC Web site.