Orac-dr is a data-reduction pipeline operating at UKIRT, JCMT, the AAT. It is part of the ORAC system. The pipeline reduces and displays multi-frame observations soon after they are read from the detector. This allows observers to assess the quality and suitability of their data in near real time. Yet Orac-dr is capable of producing publication-quality results.
Orac-dr is suitable for ‘offline’ data reduction at your home institution too. There are many reasons why you may wish to use Orac-dr in this fashion. For instance, you may have come back from UKIRT with only the raw observations; or there was an error in a telescope sequence (formerly an ‘exec’) mixing the groups of observations; or some data were reduced with a basic algorithm for speed at the telescope, and now you want to do a more-careful job. Orac-dr is capable of reducing data from instruments not running the pipeline at their respective telescopes. Hence Orac-dr is available on Starlink.
SUN/230 presents an overview of Orac-dr, general facilities like its display system, and it explains the differences between a pipeline and a traditional reduction package. Put briefly, Orac-dr uses a few data headers to direct the data reduction. Amongst these headers is the name of a recipe. A recipe is a series of high-level instructions such as “make a mosaic” or “divide by a flat” that reduces an observation comprising one or more data frames. The implementation of each of these instructions is through a Perl script—called a primitive—which calls Starlink packages such as Ccdpack and Kappa, to actually do the processing of the bulk data.
This document describes how to use Orac-dr software on Starlink to reduce data from the UKIRT imaging instruments: UFTI, UIST, IRCAM, and Michelle; the AAT imaging instrument IRIS2; the ISAAC and NACO instruments on the Very Large Telescope (VLT); Classic Cam from Magellan; NIRI from Gemini, and INGRID from the Isaac Newton Group on La Palma. It outlines the various algorithms used in the recipes, and includes detailed recipe documentation in the appendix. Besides the standard reduction recipes, this manual describes how you can customise recipes to suit your preferences, and how to correct errors in the headers of your data frames.
There are complementary documents: SUN/236 describes the Orac-dr for spectroscopy from CGS4, Michelle, and UIST; SUN/246 describes the Orac-dr for integral field spectroscopy from UIST; and SUN/231 addresses the reduction of SCUBA data with Orac-dr.
Those wishing wishing to write their own recipes from scratch, or wanting to apply ORAC-DR to new instruments should consult SUN/233.