The High Resolution Double Echelle Spectrograph HIRDES
The High Resolution Double Echelle Spectrograph
HIRDES
will provide spectra for the study of the wavelength region
110-350 nm with a resolving power R of about 50000
(6 Km/sec on the velocity scale; spectral pixel size: 0.002-0.007 nm).
This permits us to carry out deep spectral analysis of the ultraviolet
spectra of brighter stars (11-12 mag) and high resolution spectroscopy
with lower signal-to-noise ratio (SNR) for stars and other objects up to
15-17 mag, including, for example, bright stars in the Magellanic Clouds.
Since the simultaneous measurement of the whole spectral range with
such a high spectral resolution would require an array detector of a size
and a number of pixels which is not available in the near future,
the necessary wavelength range from 110 nm (MgF2 absorption edge) to
350 nm (atmospheric absorption edge) is divided into two parts. For each
of these spectral ranges one spectrograph with its own entrance slit is
optimized.
Therefore,
HIRDES is designed as a compact arrangement of two Echelle spectrographs:
- The Vaccuum Ultraviolet Echelle Spectrograph
VUVES
- 110 - 180 nm with R = 60000
- limiting stellar magnitude for given exposure time:
-> 13mag (1h) - 16mag (10h) - 18mag (100h) for SNR=10
-> 7 mag (1h) - 11mag (10h) - 13mag (100h) for SNR=100
- The Ultraviolet Echelle Spectrograph
UVES
- 178 - 350 nm with R = 48000
- limiting stellar magnitude for given exposure time:
-> 16mag (1h) - 18mag (10h) - 20mag (100h) for SNR=10
-> 9 mag (1h) - 13mag (10h) - 16mag (100h) for SNR=100
Additionally, for low dispersion spectral observations of faint objects, a low
resolution spectrograph is integrated in the UVES mounting of HIRDES:
- Long Slit Spectrograph
LSS
- (slit: 0.08mm x 5mm) with R = 500
- limiting stellar magnitude for given exposure time:
-> 20mag (1h) - 22mag (10h) - 24mag (100h) for SNR=10
-> 13mag (1h) - 17mag (10h) - 20mag (100h) for SNR=100
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suv@aip.de - T. Bloecker - 05. Feb. 1996