the new 150 ln/mm cross-disperser for the Echelle+CCD spectrograph

Munari, Tomov, Tomasella

Oct. 16, 1998

Spectroscopy in the near-IR (7500 Ang to 1.05 micron) is becoming increasingly important in literature, and the log-book of the 1.82 m evidences how it is becoming more and more interesting to Asiago observers as well.

The exploration of this spectral region at the Echelle+CCD spectrograph has been so far performed with the 300 ln/mm cross-disperser grating. The latter is however blazed in the blue and provides excessive order separation in the near-IR region (forcing therefore into multiple instrumental set-ups and exposures to cover the 7500 Ang to 1.05 micron region). To extend the spectral coverage and increase the efficiency, a new cross-disperser (150 ln/mm, blazed at 8000 Ang ) has been purchased and successfully mounted on the Echelle+CCD spectrograph.

Here we present sample Thorium, Flat and Stellar Spectra useful to document the spectral coverage and results obtainable with this new cross-disperser and with/without II-order suppressing filters.

A detailed new Technical Report (aimed to revised the N.4 by Munari & Zwitter issued in September 1994) documenting the whole spectral range of the Echelle+CCD spectrograph will be released soon.

Further details on the instrument may be found on the Asiago HomePage or questions may be posted to the Asiago Telescope Team (GAS) at

Sample Spectra