Introduction

The purpose of this section is to describe data produced by the VIS processing function. The description present in this section corresponds to the version of the VIS pipeline used for the SC8 challenge.

This section builds on the VIS Requirement Specification (RSD). However, it provides implementation-specific details. This section is intended to serve as complementary reference material for the other processing functions that expect output from the VIS-PF (in particular MER and SHE processing functions). The objective of this section is to provide a sufficient level of detail to enable these PFs to interface with the VIS-PF. The data content and formats described here should be fully consistent with the VIS data model: this document is not intended to replace the data model.

The output of the VIS PF (processing function) can be broadly divided into images and catalogues together with calibration data in the form of updated instrumental models. This calibration data can contain, for example, updated flat-fields or bias exposures, but can also contain point-spread-function models or (for example) bad pixel masks.

The imaging data products delivered correspond both to calibrated individual exposures and stacked images. For stacked images, overlapping images are combined to produce contiguous a sky coverage at each survey pointing. The dither patterns used are defined in the mission data base. In addition, associated with each of these images are auxiliary pixel data products: confidence map and Flagmap. These provide information concerning the “reliability” of each pixel. In this context, reliability means the corresponding error in flux at that pixel.

In addition to data imaging products based on science observations, the VIS PF will also deliver calibration data. In the current implementation of the pipeline, this comprises the following calibration images: a master flat and master bias. Other calibration data will include astrometric and photometric solutions for each individual image and a PSF model.

Addendum : The DPDD content is a snapshot of products generated with the current VIS PF version. However, the catalogue detailed description is completed with parameters requested by SHE to add on the next version.