NGST provides an opportunity to improve our knowledge in many fields of science and technology. It will benefit from some existing developments which have been foreseen for the largest ground telescopes and some major space observatories. This paper summaries actual technical research made at the Observatory of Paris which could be considered as a potential partner in the development of optical microcomponents for NGST.

New observations of BS and BT Cnc were performed during the STEPHI VII campaign in 1996 February. An overall run of 115 hours of data was collected. Different methods have been used to analyse the time series, bringing the detection of 2 frequencies for BT Cnc and 3 frequencies for BS Cnc above the 99% confidence level. A comparison with the literature reveals that the dominant mode of BT Cnc (similar to 9.8 c/d) has kept excited over tens of years, while the secondary modes have not been the same all the time. However, during the very last years the two frequencies detected by us have been the only ones noticeably excited in the spectrum.

Trois puéricultrices de protection maternelle et infantile (PMI) et une formatrice se sont concertées pour apporter un éclairage sur les pratiques professionnelles des puéricultrices de PMI face à la détresse sociale des familles. La rencontre de familles cumulant des problèmes socio-économiques est de plus en plus fréquente et aux familles reconnues « officiellementen difficulté comme les « RMIstesou les mères isolées s'ajoutent d'autres familles, par exemple: lorsqu'un seul parent travaille avec un salaire proche ou égal au SMIC. Il apparaît aussi des précarités nouvelles touchant des familles normalement insérées dans la société mais frappées par le chômage. Leur quotidien est envahi par la recherche de moyens financiers pour assurer le minimum vital: lait en poudre, couches, médicaments, produits d'hygiène, tickets de cantines et de transport… L'équilibre est précaire et peut entraîner la rupture: abandon du domicile par l'un des parents, violence, drogue, alcool, suicide… Les familles sont vulnérables car la précarité économique engendre une fragilité relationnelle. De ce fait, la détresse sociale à laquelle est confrontée la puéricultrice est faite de pauvreté et de marginalité.

Microlens arrays made by engraving photoresist coatings are suitable for astronomical applications, especially in the Shack-Hartmann type of wavefront sensor. Their characteristics have to be carefully chosen to fit the turbulence strength. Our instrument, composed of a photon-counting device and a Shack-Hartmann sensor, allows synchronous recordings of short-exposure images and their corresponding wavefronts. In post-processing, the point spread functions (PSF) are calculated and used to deconvolve the direct images. A new real- time centroiding device transforms this experiment into a quasi real-time imaging corrective system.

We have studied the response of a Xe-solid reflexion photocathode in a wide spectral range, from 5 key to 1.3 Mev. We compared the measured sensitivity to the gold photocathode one, in the same conditions, and found gains up to 1200 at 45 key, The linearity of the response and the gain obtained, even with this simple test experiment, enable us to envisage further developments of x-ray detectors with high efficiency and good time resolution.

S1 streak cameras with time resolution beLter than 10 ps are now currently available at the Centre d'Etudes de Limeil. They integrate a standard P 500 image converter tube slightly modified to allow the S1 photocathode's deposition. Almost 70 % of the tubes have 1.06 μm sensitivity greater than 50 pA/w and 60 % are in the 100 to 400 μA/w range. It is also possible to regenerate the 1.06 pm sensitivity when necessary, thus solving the difficult lifetime problem of these tubes. Dynamic range of a few hundreds is possible for 47 ps I.R. laser pulses and more than 64 for 12 ps pulses.