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Version 4.2 rev 06 Oct 2020
8.2 x 8.2 mm / 512 x 512 sensor
Lowest Noise Imaging EMCCD
Mechelle
After the “new” calibration parameters have been saved, all subsequent measurements will be based on these. It is
advisable to perform a one-line calibration first, as described above using a large search window, then use several line
calibration file and restrict the search window to 10 - 20 pixels. This will ensure that the optimum calibration will not
identify the wrong line. Also make sure none of the lines saturate the detector.
NOTE: To use a large number of calibration lines (>12 lines), it is recommended to use the Accumulation mode
of the detector to increase the signal-to-noise ratio of the acquired signal and therefore ensures that weaker
calibration lines are properly detected and located on the echellogramme.
Figure 17: Accumulate Settings
4.5.1 c
alibRation
F
iles
There are a number of calibration files in the list. Each file contains the calibration line information for wavelength
calibration. This file can be prepared using any editor. An example of such a Wavelength Calibration file is shown here:
The first line of the file contains a number of calibration lines. Each line entry contains the spectral order of the line and
its wavelength in μm given with an accuracy of at least 6 decimal places. Items are comma-separated. The spectral
order can be calculated as follows:
Spectral order = Order wavelength constant / wavelength (μm)
The table below shows the Order wavelength constant for each Mechelle model:
MECHELLE MODEL/ CAMERA MODEL
ORDER WAVELENGTH CONSTANT
ME 5000 / DU934 (iKon-M)
20.139
ME 5000 / DH334T (iStar 334 CCD or iStar sCMOS)
20.139
NOTE: The .xml file also contains this information.
