LHIRES2 spectrograph


See also the July 2004 Pic du Midi Observatory mission report

Spectroheliographic observation with LHIRES2 !

LHIRES2 observation of Jupiter planet near Ha line (the large feature near center) at R=17 000. The vertical lines are telluric (atmospheric water vapor). The inclined lines are the Fraunhofer lines of the Sun light reflected by Jupiter. The tilt is linked to the fast rotation of the planet (relative Doppler shift between the western and the easthern Jupiter disk)

A high resolution spectrograph for Schmidt-Cassegrain telescopes and F/8 to F/10 refractors
Un spectrographe haute-résolution pour télescopes Schmidt-Cassegrain et lunettes ouvertes à F/8-10


Dans cette page les performances de LHIRES2, des exemples de programmes scientifiques et les plans détaillés.
Click here for technical details

 1. Summary of specification

The LHIRES2 spectrograph can be used on small amateur telescopes for joint scientific programs between pro/am and for pedagogical purpose.

Le spectrographe LHIRES2 peut être utilisé sur des petits télescopes amateur dans la perspective d'une collaboration scientifique entre amateurs et professionnels, ainsi que pour une approche pédagogique et pratique de l'astrophysique.

Performance evaluation for slitless mode, for a seeing of 3 arc-seconds and an exposure of 1 hour (at 6563 A and a A0V type star)
Evaluation de la performance pour une utilisation sans fente, un seeing de 3 secondes d'arc et une heure de pose (à la longueur d'onde de 6563 A et pour une étoile de type A0V)







Lun. 128 mm
SC 200 mm
SC 300 mm


6520 - 6600
6520 - 6600
6520 - 6600




Performance evaluation for slit mode (18 microns wide), seeing of 3 arc-seconds and an exposure of 1 hour (at 6563 A and a A0V type star)
Evaluation de la performance pour une utilisation avec fente (largeur 18 microns), un seeing de 3 secondes d'arc et une heure de pose (à la longueur d'onde de 6563 A et pour une étoile de type A0V)







SC 280 mm F/D=10
600 mm F/D=10
800 mm F/D=20 (OHP)


6520 - 6600
6520 - 6600
6520 - 6600




The optical principe of a LHIRES2 type spectrograph is described here.
Le principe optique d'un spectrographe type LHIRES2 est décrit ici.

2. Resolution check

First one we compares a spectrum of the star Procyon obtained by one of the more powerful professional spectrograph, UVES mounted on a VLT 8-meters telescope, and the LHIRES2 spectrograph mounted on a 0.28m reflector (Celestron 11, December 11, 2004). The spectral resolution of UVES is about 80,000, and the spectral resolution of LHIRES2 used in slit mode is evaluated here to 17,000. Telluric lines (H2O) are removed from the LHIRES2 spectrum.

Pour tester à la fidélité et la précision on compare tout d'abord un spectre de l'étoile Procyon obtenu avec le spectrographe LHIRES2 monté sur un télescope de 0,28 mètre (Celestron 11, décembre 2004) avec un spectre réalisé avec l'un des plus puissant spectrographe actuel, UVES, installé au foyer d'un des télescope de 8 mètres du VLT. La résolution de UVES est de 80 000 environ, celle de LHIRES2 est évaluée à 17 000 (fente de 18 microns). Les raies telluriques (H20) ont été retiré du spectre LHIRES2.

The consistency of LHIRES2 and UVES spectra is excellent. This proves the good reliability of LHIRES.
La consistance du spectre LHIRES2 avec le spectre de UVES est excellente. Ce test montre la fiabilité de LHIRES2.

The following figure shows a comparison of the UVES spectrum of a K0II star and a LHIRES2 spectrum of Alpha UMa (K0I) taken with the 0.28m telescope. For clarity the LHIRES2 is shifted by +0.2 along the intensities axis.
Le figure suivante montre un spectre d'étoile K0I réalisé avec UVES et le spectre de l'étoile Alpha UMa (type K0I) réalisé avec LHIRES2 sur le télescope de 0,28 mètre: Pour des raisons de clarté le spectre LHIRES2 est décalé de +0.2 suivant l'axe des intensités.

3. Some scientific programs for LHIRES2

See also the global ARAS scientific program list
Voir aussi la liste générale des programmes scientifiques ARAS

3.1 Ha emission survey of high-luminosity supergiants

In the most luminous supergiant stars the continual or sporadic ejection of matter is a common phenomenon. Numerous stars of this type are accessible to the LHIRES2 spectrograph and a moderate aperture telescope (8-inch typically). The variability of the H alpha profile  is highly variable and spectacular on different time scales reaching from days to months. The purpose of this  survey is alert concerning exceptional events, the measure of velocity fields in the outer atmospheric region of this stars, search of pulsation or rotational modulation (tomography - dynamic spectra) and hydrodynamic studies.

The figure below concern the star Rigel (Beta Ori) and show an evidence of the variation of Ha profile if we compare a UVES spectrum and a recent LHIRES spectrum. Note that the spectral resolution of LHIRES (and LHIRES2 of course) is sufficient to resolve the lines of this area of the spectrum. Telluric lines are visible (water vapour) and have been marked ("A" letter). The wavelengths are reported to the heliocentric system. The LHIRES observation is made in Toulouse (France) with a 5-inch refractor and the cumulative exposure time is of 650 seconds.

Three days evolution of Rigel Ha profile (between February 9, 2004 and February 12, 2004) :

Another familiar star with spectrographic interest, the active supergiant Deneb (Alpha Cyg):


For a catalog and observations of supergiants click here

3.2 Observation of hot and massive stars 

Hot luminous stars, occupying the top left corner of the Hertzsprung-Russell Diagram, are some of the most spectacular inhabitants of the galaxy. They evolve quickly and encompass a range of stellar types during their lifetimes. The purpose is to explore the behavior and characteristics of evolved, massive stars and the origin of their instabilites. The stars concerned are the most hottest and the most massive of our galaxy.

Look for example short term (5 days interval!) spectacular evolution a massive bright star, Zeta Ori (the "familiar" star near the famous Horse Nebula), observed with the LHIRES spectrograph and a 5-inch refractor:

For a catalog and observations of massive stars click here

3.3 Survey of Be stars

The Be stars are defined to be rapidly rotating O, B, A-type stars of luminosity classes III-V which Balmer emission lines. Many B stars show these characteristics, but the Be stars correspond only to the class of non-supergiants (classes III to V). Approximately 10% of the non-supergiant B-type stars present the characteristics of the Be stars.

A characteristic of the Be stars comes from the variability of aspect of the hydrogen lines (and sometimes, helium and iron). Stars can on a cycle of a few years show lines in strong emission, usually completely absent (confused with the continuum) or in absorption as in a normal star. The frequency of the variations of  the profile lines covers a very broad range since some Be stars can show certain line-profile changes in a few hours or minutes whereas others can remain stable during years. Sometimes several cycles of variations with very different periods can be superimposed. For a complete review about Be stars, click here.

An example, the time evolution of the star Zeta Tau:


For a catalog and observations of Be stars click here

3.4 RS CVn stars

RS CVn are class of detached binary typically composed of a chromospherically active G or K stars. The system generally rotate fast with typical orbital period from a few days to 20 days. Tidal forces between the close components have locked  their rotational periods to the orbital period. The RS CVn binaries display a high level of activity with strong chromospheric line emissions. One of the striking aspects of these systems is their propensity to flare. These stars shows rotational modulation of photospheric spots.and are also magnetically active (Doppler Imaging and Zeeman Doppler Imaging are classical technique used for map stellar surfaces of the RS CVn components).

Here the two days evolution of the RS CVn star UX Aries:


For a catalog and observations of RS CVn stars click here

3.5 Spectroscopic double starsSurvey of Be stars

For pedagogical purpose (fine demonstration of Doppler effect and celestial mechanic) and because these objects are spectacular, the spectroscopic binary. Example, the fast swing of the component of 12 Boo:


For observations of spectroscopic double stars click here

3. Design

Conception André Rondi et Christian Buil

Technical documentation, click here
Documentation technique, cliquer ici
Mise à jour : décembre 2004 - Updated: December, 2004

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