The sky-subtraction performance of multifiber spectrographs is discussed, analyzing in detail the case of the OPTOPUS system at the 3.6-m ESO telescope at La Silla. A standard technique, based on flat fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the [O I] emission line at 5577 angstrom as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent ones, and correcting for the effects of the image distortions on the sky sampling. In this way the accuracy of the sky subtraction improves from 2%-8% to 1.3%-1.6%.
Lissandrini, C., Cristiani, S., LA FRANCA, F. (1994). SKY SUBTRACTION WITH FIBER SPECTROGRAPHS. PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC, 106(705), 1157-1164 [10.1086/133493].
SKY SUBTRACTION WITH FIBER SPECTROGRAPHS
LA FRANCA, Fabio
1994-01-01
Abstract
The sky-subtraction performance of multifiber spectrographs is discussed, analyzing in detail the case of the OPTOPUS system at the 3.6-m ESO telescope at La Silla. A standard technique, based on flat fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the [O I] emission line at 5577 angstrom as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent ones, and correcting for the effects of the image distortions on the sky sampling. In this way the accuracy of the sky subtraction improves from 2%-8% to 1.3%-1.6%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
