|Wavelength [Å]||Pre Slit||Mirrors||Echelle||Crossd.||Camera||CCD||Total|
Assuming these efficiencies and an efficiency of 60% for the 1.52-m telescope, a spectrum of a 10th magnitude star can be taken in 15 min with a S/N=100 per pixel in V (cf. figure below). Within one hour for a star of 16th magnitude star still a S/N of 10 is reached.
These numbers were derived assuming a slit length of 10 pixels, each pixel contributing with a read-out noise of 3 electrons and a dark current of 4 electrons/hour as given by the CCD characteristics.
Updated on August 18, 1998 (includes now measured efficiencies of
microlens, fiber, F/N system, image slicer, echelle, collimators,
crossdisperser prims, camera, field lens, and science grade
detector (measured by EEV).
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 10:45:00 MET 2001