May 19, 2017
We recently discovered an error in our BANZAI data pipeline. In the source catalogs (i.e. the .CAT extensions) that accompany the reduced images, the set of FLUXAPER* keywords are used to indicate the source fluxes within circular apertures of * arcseconds in diameter. For example, FLUXAPER3 is the source flux in a 3-arcsec diameter aperture. ----- The error in the pipeline was that the fluxes were being calculated within circular apertures of * pixels (rather than arcseconds) in diameter. So, in the example above, FLUXAPER3 was actually the source flux in a 3-pixel diameter aperture, even though the description in the header said 3-arcsecond diameter.
The problem has now been fixed. Beginning with images from the night of 20170516, the fluxes of catalog sources in BANZAI-processed images are being correctly calculated (in arcsecond apertures) in the headers. The pipeline version number has been incremented. If the header keyword PIPEVER is 0.7.9dev1194, the fluxes are for apertures measured in pixels. If the header keyword PIPEVER is 0.7.9dev1197, the fluxes are for apertures measured in arcseconds.
We apologize for the inconvenience.
Return to Highlights