!CDS Quicklook Software

How to get started

After entering IDL we need to read a CDS FITS file
containing science data. This can either be done by
calling the routine READCDSFITS and specifying a
certain file or by using a menu that will display
the data files available.  We start with the last
approach since you then do not need to know were
files are located. The routine to use is called
QL_MENU and is invoked by

  IDL> ql_menu

A widget menu will appear where you can select a
file to be read into IDL.  This routine will call
READCDSFITS, which retrieves the data in the CDS
FITS file (see below). The Main QL menu will
thereafter appear. Thus, you are now running the
software in Menu-mode.

The method of interactively reading an observation
sequence into IDL is to use the function
READCDSFITS.  (To read the data obtained during the
instrument calibration testing use the function
READCALFITS.)

  IDL> a = readcdsfits('testdata2.fits')
  IDL> a = readcdsfits(concat_dir('$CDS_NIS','testdata2.fits'))

The latter specifies the directory using the routine
CONCAT_DIR.  READCDSFITS returns the entire contents
of the file in an anonymous IDL structure variable
called a QuickLook Data Structure (QLDS).
A set of data cubes, one for each line window in the FITS file,
resides within the QLDS and can easily be passed
between different routines.


!CDS data structure

The CDS data structure:

To be written....



!WAVELENGTH SLICE/PROFILE

WAVELENGTH SLICE/PROFILE:

Display data slices at specific wavelength together
with line profiles.  A window is created with two
types of display of the data in four selected
spectral windows.  The upper display is a cross
section of the data at a specific wavelength,
giving a spatial view of the region that has been
scanned by the CDS NIS/GIS.  The lower display is
the intensity profile along the dispersion
direction (line profile), at a selected point in
the two-dimensional image displayed in the window
above.

Although only four spectral windows may be shown on
screen at any time, it is possible to select which
spectral windows is to be shown in which panel by
using the pulldown menu between the upper and lower
displays.


!Cursor Action

Cursor Action

The mouse buttons have the following actions:


  B1: select point/wavelength of interest (see 1)
  B2: extract profiles  (see 2)
  B3: zooming (see 3)

 1) Select point/wavelength:  

	To change the spatial views from one wavelength to
	another, click on the line profile at the desired
	wavelength.

	The point from which the line profile is taken is
	selected by clicking the left mouse button in the
	spatial view, and it is marked by a cross in the
	spatial view.  Incremental positioning is done by
	clicking the left mouse button outside the axes of
	the displayed area.  The point/cross is then moved
	one pixel in the direction of the mouse marker.
        
        The current position is displayed in the text labels
        on the right hand side.

 2) Extract profiles

	Extract profiles by clicking mouse button 2 in the
	spatial view. A profile window will appear where
	the length and height of the area of interest can
	be be adjusted with widget sliders (see description
	of PQLPROFILE).

 3) Zooming

	Extract a zoomed image of an area of interest by
	clicking mouse button 3 in the spatial view.  Zoom
	in and out by clicking mouse buttons 1 and 3 while
	the cursor resides within the zoom window.


!   1) Select point/wavelength

Select point/wavelength:  

To change the spatial views from one wavelength to
another, click on the line profile at the desired
wavelength.

The point from which the line profile is taken is
selected by clicking the left mouse button in the
spatial view, and it is marked by a cross in the
spatial view.  Incremental positioning is done by
clicking the left mouse button outside the axes of
the displayed area.  The point/cross is then moved
one pixel in the direction of the mouse marker.

The current position is displayed in the text labels
on the right hand side.

!   2) Extract profiles

Extract profiles:

Extract profiles by clicking mouse button 2 in the
spatial view. A profile window will appear where
the length and height of the area of interest can
be be adjusted with widget sliders (see description
of PQLPROFILE).

!   3) Zooming

Zooming:

Extract a zoomed image of an area of interest by
clicking mouse button 3 in the spatial view.  Zoom
in and out by clicking mouse buttons 1 and 3 while
the cursor resides within the zoom window.



!Window Line

Window Line: (Buttons between the upper/lower windows)

Select the spectral line to be displayed in the
draw window.  A menu appear with all existing lines
in the current data set.

!Hard Copy

Hard Copy:

Create a postscript plot of the entire spectrum
(screen) to be printed or saved to file.

!Line Fit

Line Fit:

Line fitting routiens to be applied to the
displayed profiles.  The properties like intensity,
FWHM and shifts will be displayed in text labels
below the plot windows.

!Diagnostics

Diagnostics:

Option of deriving temperature maps (images) or
density maps.


!Slit Location

Slit Location:

A full disk image of the Sun is displayed in a
window, and the coordinates in the QLDS are used to
plot a box depicting the position from where the
exposures stem.  Various full disk observations,
either ground based or from space will be
available.

!Help

Help:

Activating the QL Help widget where information
about how to use the different features in the
DSPWAV window are shown.  By selecting one of the
options, information about this feature will be
displayed in the text window to the right.

!Done

Done: 

When the DONE button is pressed the DSPWAV window
is exitted and all related widget interfaces are
destroyed.
