1. Introduction

This tutorial covers the basics of reducing Flamingos-2 data using DRAGONS.

The next two sections explain what are the required software and the data set that we use throughout the tutorial. Chapter 2: Data Reduction contains a quick example on how to reduce data using the DRAGONS command line tools. Chapter 3: Reduction with API shows how we can reduce the data using DRAGONS packages from within Python.

1.1. Software Requirements

Before you start, make sure you have DRAGONS properly installed and configured on your machine. You can test that by typing the following commands:

$ conda activate dragons
$ python -c "import astrodata"

Where dragons is the name of the conda environment where DRAGONS has been installed. If you have an error message, make sure:

  • Conda is properly installed;
  • A Conda Virtual Environment is properly created and is active;
  • DRAGONS was successfully installed within the Conda Virtual Environment;

1.2. Downloading the tutorial datasets

All the data needed to run this tutorial are found in the tutorial’s data package:

Download it and unpack it somewhere convenient.

cd <somewhere convenient>
tar xvf f2img_tutorial_datapkg-v1.tar
bunzip2 f2img_tutorial/playdata/*.bz2

The datasets are found in the subdirectory f2img_tutorial/playdata, and we will work in the subdirectory named f2img_tutorial/playground.


All the raw data can also be downloaded from the Gemini Observatory Archive. Using the tutorial data package is probably more convenient but if you really want to learn how to search for and retrieve the data yourself, see the step-by-step instructions in the appendix, Downloading from the Gemini Observatory Archive.

1.3. About the dataset

1.3.1. Dither-on-target

This is a Flamingos-2 imaging observation of a star and distant galaxy field with dither on target for sky subtraction.

The calibrations we use in this example include:

  • Darks for the science frames.
  • Flats, as a sequence of lamps-on and lamps-off exposures.
  • Short darks to use with the flats to create a bad pixel mask.

The table below contains a summary of the files needed for this example:

Y-band, 120 s
2 s, short darks for BPM
120 s, for science data
20 s, Lamp On, Y-band
20 s, Lamp Off, Y-band