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Frequently Asked Questions

Before going in more detail, if you have any question about installation or due to failure while reducing data, please check our FAQ. it may have been answered before.

Automated data reduction for FIES

Reducing echelle data can be a time-consuming process, especially if it is the first time an observer obtains data from a new instrument. Data reduction is also not what an observer wants to be spending time on during an observing run. However, to be able to make strategic decisions during an observing run, data reduction during observations is essential. In particular, it is important to get a quick first impression of the data. For these reasons, there is a strong desire for the automatic reduction of data already at the telescope.

FIES (FIber-fed Echelle Spectrograph) at the Nordic Optical Telescope is a high-resolution spectrograph, available on a stand-by basis. This means that an observer has the possibility to execute observing programs that need flexible scheduling, such as long-term studies of objects with day-to-day variability, or target-of-opportunity programs that require a high-resolution spectrograph to be available. It is very likely that such programs will be executed in service mode. Automatic reduction of observations will then be an important complement to such observing modes. Automatic reduction also standardizes the reduction procedure and will simplify the user's effort by offering a default setup of reduction parameters

FIEStool was developed just for this purpose. FIEStool is written in Python, an object-oriented language that provides easy interfacing between the user, through a Graphical User Interface, and specialized reduction tasks from the external packages IRAF and NumArray, both developed at STScI. It is capable of automatically reducing data obtained with FIES, while at the same time providing the user the possibility to control the basic properties of the reduction process by hand.

An important requirement when developing this software was that it should be flexible, so it will be possible to adapt the software to future changes in the data format or instrument characteristics. In fact, the core of FIEStool is written completely instrument-independent, so that the software could, with minor modifications, also be used for automatic reduction of data from other instruments.

This manual gives a detailed description of the user interface and the underlying routines, as well as instructions on how to modify the software if that would be necessary. Still, the only way to really learn how to use FIEStool, for data reduction, is by using it.

The Virtual Machine

FIEStool is written in Python, which is ubiquitous in modern Linux and OS X systems, and depends on a number of standard modules used by astrophysics software packages (like NumPy or PyFITS). But it also needs IRAF/PyRAF and a few other not-so-common things.

For the convenience of the non-tech savvy, or those that just want to start using FIEStool right away we've produced a Virtual Machine to help you starting to work with FIEStool with the minimum trouble.

Source code and requirements

FIEStool was developed on a 2.4 GHz computer with 512 MB of memory running Linux.

FIEStool makes use of the following software packages. A more complete list is included in the manual. Version numbers are the minimum required.

IRAF patch for simultaneous ThAr

Due to rounding errors, IRAF cannot record high-precision wavelenght shifts. In case that you're using FIEStool in the DoubleSpec mode for Simultanous ThAr, you can apply a patch to IRAF to correct this problem.


Database of Master frames

Download FIEStool

  • One-but-latest version (Oct 2018): FIEStool-1.5.1.tar.gz (Python 2.7)
    For documentation see the links above.

  • Latest version (Aug 2022): FIEStool-1.5.2.tar.gz (Python 2.7)
    For documentation see the links above.

MIDAS scripts

Andreas Irrgang (Bamberg) has written a few MIDAS scripts that can be used to reduce FIES data in the MIDAS environment. These scripts are not maintained by NOT staff. Please contact Andreas for details.

CERES collection

Rafael Brahm has setup a collection of pipelines to reduce echelle spectra for a set of instruments, including FIES. CERES can be downloaded from github. More information can be found there and in the paper CERES: A Set of Automated Routines for Echelle Spectra. These scripts are not maintained by NOT staff. Please contact the author for details.
Back to top Last modified: April 19 2023