UCLES Wavelengths

The Coude Echelle Spectrographs

2.2 Selecting Wavelengths for UCLES

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To calculate the central wavelength and determine the wavelength coverage for your observation, use ECHWIND. This program allows the user to display the UCLES echellogram on an Xterminal and to superimpose spectral line identifications and detector windows to determine interactively the optimum setup.

ECHWIND has been released as a Starlink program and should be run at your home institution when preparing an observing proposal.

Starting ECHWIND

You can access ECHWIND an a unix machine at an AAO site by:

>figaro
>echwind

Alternatively, in user account obsred on aatssf , you can start up the utilities menu (AAT) and find ECHWIND under `setups'. CHECK MENU NAME

The program prompts for initial values of the following parameters (you can change most of them afterwards):

CONFIG - Instrument Configuration? /UES/31/LONG/ >
Enter the required echelle grating (31 or 79, 31 is default) .
DETLIST - File containing user detector list? >
(Optional) Your prepared file listing detector area (in mm) in the format:
detector name xx yy
DETSYSTEM - File containing system detector list? >
System list of detector areas (in mm). Default (detectors.dat) is OK for AAO sites.
WHY IS MITLL MISSING?
Detector (TEK, (etc) or xx,yy in mm)? >
List in prompt will include detectors in DETLIST and DETSYSTEM. Select your detector, or enter the dimensions as prompted.
ANGWAVE - Slit angle offset or wavelength? >
If unsure, enter central wavelength and ECHWIND will calculate the slit angle offset.
MORE INFO?
WAVE - Central wavelength? >
Central wavelength in angstroms.
LINES - File containing line list? >
(Optional) Prepared file listing spectral lines or positions you wish to have flagged on the display. The file has the format:
wavelength 'label'
e.g.
6562.80 'HA'
4861.32 'HB'
Graphics device/type (? to see list, default /XWIN):
Enter ? to get list, e.g. /xwindow. The device must have a cursor for the program to run. For a hardcopy, select /ps or /vps which will create a file pgplot.ps and exit the program.
ONLY PS?

Running ECHWIND

Once ECHWIND is started, a graphics window is started. To use the program options, press any mouse button which will start a menu in the window. Clicking in the plot area will centre the detector box at the cursor position. The menu item is selected by clicking on the desired function. Current options are:

Clear BOXES :

Delete BOX :
Remove the last detector window drawn.

Mark BOX :
Mark the current position of the detector with a green box.

Mark LINES :
Enter a filename.DAT file containing wavelengths and identifications, as described above. The program prompts for the filename in your original window.

New ECHELLE :
Swap between the 31.6 and 79 lines/mm echelles.

New DETECTOR :
Change to a new detector size.

New ANGLE :
Change to a new slit angle offset.

New WAVELENGTH :
change to a new central wavelength.

x 1.3, x 2.0, etc :
Zoom in/out on detector window.

CENTRE :
Replot the echellogram centered on the detector position.

SAVE :
Output the echelle parameters to a control file. The program prompts for the name of the output file. This file can be used to configure the spectrograph, though all that is really required is the central wavelength which ECHWIND displays.

EXIT :
Leave the program.

Ray Stathakis (ras@aaoepp.aao.gov.au)
Last Update: 21 March 2000