1 Introduction

The Submillimetre Common User Bolometer Array-2 (SCUBA-2) is a large-format bolometer camera for the 15-m James Clerk Maxwell Telescope, designed to produce simultaneous continuum images with central wavelengths at 450 and 850 μm.

The purpose of this guide is to help SCUBA-2 users become familiar with the basic facilities for analysing and visualising data using Smurf[1], and the Starlink packages Kappa[3], and Gaia[4]. Obviously, Starlink must be installed on your system, and Starlink aliases and environment variables must be defined before attempting any of the examples in this document. This guide is not aimed at users of the polarimeter (POL-2) or Fourier transform spectrometer (FTS-2).

A brief description of raw SCUBA-2 data is given in Section 2. Section 3 demonstrates how to visualise SCUBA-2 data, interspersed with some simple worked examples of interactive data-reduction techniques. The end goal of this section is not to produce a final science-grade map, rather to give the user a feel for the types of artefacts and data reduction steps required to make a useful image. The best way to make an image from SCUBA-2 data is to use the Dynamic Iterative Map-Maker (DIMM). This one-line command and a subset of its control parameters are described in Section 4. We then discuss data calibration (§5) and provide worked examples of cosmology (§6.1) and Galactic (§6.2) data reduction. For the user who wishes only to produce maps in as little time as possible, jump straight to these later sections.

Note that a number of the examples in this document use real data that are distributed with this Starlink release. The small Uranus example is distributed as part of SMURF and can be found in:


The more detailed examples use larger data sets which, because of their size, can be downloaded separately via the URL http://www.starlink.ac.uk/extras/sc19/. If you wish to use these data for scientific purposes (i.e. leading to a publication), explicit permission must be obtained from the Director of the James Clerk Maxwell Telescope.

To gain access to Smurf tasks (the data reduction package for SCUBA-2) before proceeding with the examples in this document first type:

  % smurf
          SMURF commands are now available -- (Version 1.3.1)
          Type smurfhelp for help on SMURF commands.
          Type ’showme sun258’ to browse the hypertext documentation.
          Type ’showme sc19’ to view the SCUBA-2 map-making cookbook.

For a more detailed description refer to the comprehensive Starlink User Note (SUN/258)1.

1currently SUN/258 is not completely up to date