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