1. Overview

This is a tutorial for the reduction of GNIRS longslit spectroscopic data with DRAGONS.

GNIRS is a near-IR spectrograph offering longslit spectroscopy, cross-dispersed spectroscopy, and intergral field spectroscopy (aka IFU). This tutorial focuses on the longslit spectroscopy.

For cross-dispersed spectroscopy, see GNIRS Cross-Dispersed Data Reduction Tutorial.

Note that the acquisition keyhole can be used as an imager when no other near-IR imager is available on the telescope and the science is time sensitive. For a tutorial on the reduction of GNIRS keyhole imaging data, see GNIRS Imaging Data Reduction Tutorial.

In this tutorial, you will be able to run the examples yourself and experiment with the process. The tutorial comes with downloadable data packages that contains all the data you need to run the examples presented. Instructions on where to get that package and how to set things up are given in Downloading tutorial datasets.

The GNIRS longslit tutorial series contains four scientific examples covering non-thermal and thermal bands, and grating settings.

The reduction can be done in two different ways:

• From the terminal using the command line.

• From Python using the DRAGONS classes and functions.

We show how to run the same reduction using both methods.

The tutorials are:

• K-band 32 l/mm grating

• J-band 111 l/mm grating

• L-band 10 l/mm grating

• K-band beyond 2.3 microns 111 l/mm grating

See the DRAGONS Installation Instructions to install the software if you have not already.

Tip

If you are using the tutorials to guide you through the reduction of your own data and you encounter a problem, please review the Tips and Tricks and Issues and Limitations sections. They may contain the solution to your problem.

Also, please use the Wavelength Calibration Guide for GNIRS LS to help you choose the best way to wavelength calibrate your data.