Long-slit Intermediate Resolution Infrared Spectrograph for the WHT
This software is intended to be used in order
to perform a quick analysis of the LIRIS data while observing at the telescope,
but is not intented to provide fully reduced data. It is developed as an
IRAF package, easy to install at any place.
This package, its documentation and the information given here have been created by Jose Acosta at IAC. This package is largely based on the similar package, ingrid_ql, developed by Robert Greimel at ING.
Using the LIRIS quick look package
To use the LIRIS quick look package:
Open an ximtool (or another display tool) to display the data (i.e. type ximtool& or ds9&, for example).
Start an IRAF session: open an xgterm, change to the home directory and
type cl (or ncl). The prompt will change
Type: cl> liris_ql. The prompt will change to li>
Type: li>help usage, to get information about the use of the package
Type: li>help to get a list of the available tasks.
Type: li>help task_name to get more information on using each particular task.
Some of the most frequently used tasks are:
idedither - combine dithered images
idispframe - display frame (post-pre)
istarfocus - find focus from focusrun images
icombine - combine images
ifindron - find readout noise from two dark frames
iframediff - calculate and store post-pre
ilistdark - list dark exposure times needed
istatistics - calculate image statistics
isubtract - subtract two images
When you take an exposure with LIRIS the array
is reset and immediately read out. This is called the pre-read image, and
is stored in extention 1 of the file (rNNNNNN.fit[*,*,1]). After the exposure time has passed the array is read out again. This is
called the post-read image and is stored to the extention 2 of file (rNNNNNN.fit[*,*,2]). The information useful for the observer is
the difference between these two images. The liris_ql package provides a quick way to access this information.
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