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:
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.

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.

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'
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 and exit the program.


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:

Ray Stathakis (
Last Update: 21 March 2000