Heros Homepage

Instrument Description

HEROS is a portable fiber-linked two-channel echelle spectrograph designed and built by A.Kaufer, H.Mandel, O.Stahl, B.Wolf and I.Appenzeller in 1994.

Click here to see a schematic layout of the telescope unit

Pictures of the telescope unit at the ESO Dutch.90-m telescope

The HEROS fiber head.

Click here to see a schematic layout of the instrument

Click here to see a perspective view of the instrument

Pictures of the HEROS spectrograph

Fiber: 100 micron core diameter
Collimator: f/4.5, f=360 mm
R2 Echelle grating: 31.6 grooves/mm, blaze angle 63.4 deg

Red Channel:
Cross disperser: 300 grooves/mm, blaze wavelength 5000 Angstroms
Camera: f/2.8, f=300 mm
CCD: EEV 1152x770, 22 micron pixel, LN2 cooled
Blue Channel:
Cross disperser: 400 grooves/mm, blaze wavelength 3900 Angstroms
Camera: f/2.8, f= 300mm, UV transmittance down to 3500 Angstroms
CCD: EEV 1170x800, 22 micron Pixel, LN2 cooled. This CCD was replaced replaced by a LN2 cooled SiTE 2000x800 CCD with 15 micron pixels in 1996. This thinned and back-illuminated has a quantum efficiency of more than 70 percent at 3500 A

The light-weight telescope unit with the TV-guiding sytems (30 kg) is easily attachable even to telescopes of the sub-meter class and is used to guide the star on the fiber during exposure. Further it contains the lamps (flatfield: halogen; wavelength comparison: hollow-cathode Thorium-Argon) for the fiber-fed calibration exposures.

Capabilities

Free Spectral Range: 3450 - 5600 and 5800 - 8650 Angstroms in one exposure
Resolution: lam/dlam = 20000 over the complete wavelength range
Signal-to-Noise: 100 in 1 hour with a 50cm-telescope for a 6th magnitude star
Radial-Velocity Accuracy: < 1 km/s

Data Reduction

The spectra are reduced semi-automatically in a modified ESO-MIDAS Echelle-context.
The red and blue channel are reduced separately in the following steps:

Order definition and optimal extraction
Flatfielding of the extracted spectra
Wavelength calibration with a 2D global fit for the dispersion coefficients
Rebinning to wavelength scale and heliocentric correction
Merging of the order and normalization of the spectra
Archiving of the spectra in a data base

Scientific Programs

Due to its high spectral stability, large wavelength coverage and high resolution HEROS is predestinated for variability studies of stars. In January - June 1995 HEROS has successfully been used in an extended observing campaign (120 nights !) at the ESO 50-cm-telescope at La Silla for monitoring the wind and photospheric variability of hot OBA supergiants and the chromospheric variability of cool K-giants.

Results of these extended spectroscopic monitoring programs can be found on the Hot Star Page of the Landessternwarte.

Data archive

The Heros data are archived. The archive can be searched here.

If you have any comments on this page, please send me a mail .

HEROS home page / akaufer@eso.org

Last modified: Fri Jan 26 15:03:10 MET 2001