The 2. NEON school at Haute-Provence Observatory (France)

The second NEON observing school took place at Haute-Provence Observatory from July 9 to 21, 2001. Sixteen students from 11 different nationalities used the 4 largest telescopes of the observatory during 5 nights to conduct scientific programs under the guidance of experienced tutors. The 1.93m and 1.52m telescopes were used for spectroscopy, in low- and high-dispersion spectroscopy respectively, while the 1.20m and 0.80m were used for CCD imaging. The later telescope, pointed manually, with cupper engraved circles for declination and hour angle (not right ascension...) readings, was used also for visual observations of nice objects: Mars at the beginning of the night, the Planetary Nebula in Lyra, Globular clusters, Comet Linear, M31, Venus, etc... This was for many the first (and probably the last...) opportunity to use such a large telescope for visual observations. The reaction is not the same, when you see your telescope dangerously approaching the horizontal platform, or when you simply get a computer message saying "software pointing limit"...

The observations were preceded by several introductory lectures giving the necessary basis. Cesare Barbieri (Padova) presented the various optical combinations used in telescopes, with active and adaptive optics, and gave an opening on future giant (100m ?) telescopes. Michel Dennefeld (Paris), after recalling the basic properties of CCD detectors, focused on the various steps necessary to perform low-dispersion spectroscopy. Sergio Ilovaiski (Haute-Provence) described the delicate photometric observations and their limitations. And Denis Gillet (Haute-Provence) tried to convince us that the only valid technique to get physical parameters of astronomical objects was to use high-dispersion spectroscopy....if the objects were bright enough (fortunately the VLT opens new perpsectives in this respect!). Later, Richard Hook (ESO-StECF) described the steps and algorythms used for image analysis, while Emmanuel Bertin (Paris) focused on the reduction of wide-field images, with the requirements in computing power and storage space, producing at the end catalogues of billions of objects with his favoured extraction algorythm, Sextractor. The simultaneous presence of teachers, tutors and students for a large fraction of the school, together with nice wheather, provided ample opportunities for relaxed, but fruitfull discussions.

But the main aspect of the school was of course the observations. Preparation of the program, observations themselves, data reduction, and analysis were performed in small groups of 3 students, each under the dedicated supervision of an experienced observer. Philippe Mathias (Nice) proposed to his group to follow spectroscopically the variations of a Beta Cephei star, BW Vulpeculae, during a full cycle of 5 hours. Line doubling was observed, a variation of the stellar radius derived and all this interpreted in the frame of a shock wave propagating from the deeper layers into the upper atmosphere of the star. Santos Pedraz (Calar Alto) derived with his group the dynamical structure of 3 dwarf elliptical galaxies, M32, N185 and N6020, and determined their stellar populations by comparison with models. A comparison with a giant elliptical, N6411, was also proposed. Thomas Rivinius (ESO) and his group observed three different Be stars at high spectral resolution (38000): Pi Aquarii (highly variable), 31 Pegasi (pulsating) and 66 Ophiuci (composite), and demonstrated in the latter case, by identifying two new spectral components, that this was in fact a triple system! They also showed, after imaging with interference filters, that the galactic cluster N7419 contained in fact a very large fraction of emission line (Be?) stars. Alessandro Pizzella (Padova) measured with his group the rotation curve of 3 galaxies: IC1210 (Sab), N7177 (SBb) and N6764 (SBbc), deriving their mass profile. For the same objects, CCD photometry gave their light profile, hence the derivation of the M/L ratio. It was demonstrated, for N7177, by adjustement of a bulge and a disk component, that this galaxy had indeed a bar. And finally, Anna Pasquali (ESO-StECF) and her group, the only four-leaved clove, studied the bipolar Planetary Nebula He2-437, dubbed the "moustache", and derived its excitation and abundance profile. But the occurence of targets of opportunities, and the enthousiasm of that group which happened to be at the telescope at that time led it to do additionnal work (but I know other groups would have been keen to do the same...): asteroid 5587 (1990SB) was followed photometrically during more than a rotation period, to derive a light curve, and SN 2001da, discovered by the Berkeley group just two days before, was identifed as a type Ia Supernova caught just before the maximum (IAUC  7664). And then started the long (painfull? It does not look like that...) work of data reductions....

All this ended by an oral presentation of the results, the last day of the school. For many participants, this was a "premiere"... and presenting data in a precise, yet concise form is also something one has to learn, specially if one has to use a strange language, which is not your mother may even seem lost sometimes!

but all were succesfull! For B. Aracil (Paris), A. Bik (Amsterdam), A. Castillo (Liverpool), J.M. Desert (Paris), D. Faria (Lund), Y. Goranova (Sofia), F. McGroarty (Dublin), M. Maintz (Heidelberg), S. Marchi (Padova), Th. Nakos (Brussels), J. Nirski (Torun), M. Paolillo (Palermo), S. Potanin (Moscow), D. Rizzo (Milano), M. Stuhlinger (Tuebingen) and M. Vanko (Proprad) the school was an interesting and rich experience of joint work in a european atmosphere. Many collaborations have started here, and some of the results will be published in the near future.

But, true, the school was not only about observations! High-technology was also on the program. Antoine Labeyrie gave an enlightening presentation on hypertelescopes, densified pupils, large interferometers on the moon, .... followed by a detailed look at the only existing "futuristic" telescope, a 1.5m with a mirror in ordinary glass, housed at OHP in a spherical mount which was seen up to now only in science fiction novels!

And next door, a visit to the assembly hall where VIMOS is in its final testing showed the complexitiy of modern VLT instrumentation. The geophysical station, located in the same observatory, with its many lasers sounding the atmosphere, showed us that basic science is some times not far from real life considerations: ozone measurements are done routinely without even disturbing the astronomical observations. And last but not least, dayly approach of french cuisine, the flavour of thym and lavander, the taste of pastis,...convinced everybody that hard work is not uncompatible with enjoying life. This was a real summer school!

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