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;

AstroConda (STScI) is properly installed within the Virtual Environment;

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:

http://www.gemini.edu/sciops/data/software/datapkgs/f2img_tutorial_datapkg-v1.tar

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.

Note

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:

Science	S20131121S0075-083	Y-band, 120 s
Darks	S20131121S0369-375	2 s, short darks for BPM
Darks	S20131120S0115-120 S20131121S0010 S20131122S0012 S20131122S0438-439	120 s, for science data
Flats	S20131129S0320-323	20 s, Lamp On, Y-band
Flats	S20131126S1111-116	20 s, Lamp Off, Y-band