Search

The paper shows some operational techniques for the characterisation and mapping of pastoral resources in mountain areas. The utility of multispectral images was evaluated to produce thematic cartography of the studied pastures and to determine their pastoral value, a useful parameter for management purposes. Data collected by the multispectral ASTER sensor, with a 15 m spatial resolution in the VISNIR, 30 m in the SWIR, and 90 m in TIR, and the MODIS sensor, with a daily temporal step and a 250 m spatial resolution, were used. The images are classified using a maximum likelihood algorithm, while multivariate locally calibrated regression is applied to extend the pastoral value over the whole area. Results show a low capability of the satellite images in discriminating the different pasture vegetation types, whereas the assessment of pastoral value produces more promising achievements (r = 0.647;, RMSE = 6.99).

In the recent years more and more countries around the world have been concerned with space debris detection and monitoring. In Italy, although satellites and debris have been definitely, though not intentionally, detected by astronomers in the last decades, dedicated observations have never been performed before April 2002. In this month the Group of Astrodynamics of the University of Rome “La Sapienza” (GAUSS) started an optical survey of the geostationary ring from the Campo Catino Astronomical Observatory. This observatory, owned by the “Associazione Astronomica Frusinate” (Frosinone Astronomical Society), is one of the best amateur astronomers’ facilities in Italy: his dome hosts an 80 cm aperture Ritchey-Chrétien telescope, a 25 cm Baker-Schmidt and a 15 cm refractor, while a 40 cm Ritchey-Chrétien is going to be operated in another dome; two CCD sensors are available for such telescopes. For this first GEO campaign, the 25 cm Baker-Schmidt device was chosen, in order to have a wide field of view: the telescope was coupled with an AP-8 10241024 CCD, resulting in a 1°, 50’ FOV. The first nights of observation were dedicated to a survey of the GEO ring: about 90 degrees of right ascension were spanned, collecting several hundreds images and detecting about 100 objects; as the CCD read-out time is about 35 seconds, a relatively long exposure time (20 seconds) was selected, to improve the ratio of exposure time to gap time between frames. The telescope was pointed in a star-tracking mode, so the Earth satellites are easily detected as stripes on a dot-shaped background of stars; hence, two points of the track (lead and trailing edges) per image are generally identified in terms of topocentric right ascension and declination. Moreover, the observed star field is kept constant along some hours of observation, letting the GEO ring cross such field. The data processing, presently managed off-line, is now being carried out, in order to identify the objects and determine their orbits. Of course other observations will be performed in the next months. In the paper the campaign status is described in detail and the results are presented.