Spectral Format

The image slicer output equals two slits (object + sky/external calibration) in 0.9 mm distance with a 120x600 micron aperture. For each order this leads to slit images on the detector with a size of 2.2x10.9 pixels and 16.4 pixels separation in crossdispersion direction leaving a sufficient fixed interorder space of 5.5 pixels for the background definition. The distance between two orders is smallest in the red with about 30 pixels and increases to about 100 pixels in the blue.

A schematic layout of the 35 orders on the detector in the standard setup is shown in the following figure for a single fiber.

[Spectral Format]

A detailed simulation of the raw spectra including the object & sky fibers, the blaze function, the total transmission, the detector efficiency, the image slicer, and the intrinsic spectrum of the light source can be performed in the MIDAS environment.

The spectral range from 3680 to 8550 Å is available in one exposure for the object and sky/calibration spectra. The wavelength range above 8550 Å up to 9200 Å (absorption edge of the fiber) is in principle also available on the detector, but with small gaps in the spectral coverage. By a simple turn of the crossdisperser prism by 0.5 degrees, the wavelength region from 3500 to 6800 Å is accessible without refocussing of the spectrograph camera.




If you have any comments on the FEROS project, please send me a mail .

FEROS homepage / A.Kaufer@lsw.uni-heidelberg.de
Last modified: Fri Jan 26 10:10:19 MET 2001