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The GEOS, Groupe Européen d’Observation Stellaires, is composed of observers living in France, Italy, Spain, Belgium and Switzerland. The main purpose is to give amateur astronomers the opportunity of carrying out scientific analyses in specific fields. Further details can be found at the web site http://www.upv.es/geos/In the past years, GEOS has approached the analysis of visual estimates of variable stars (Ralincourt et al., 1987) in an original manner, obtaining accurate light curves on red semiregulars. Moreover, the collaboration with teams of professional researchers allowed the group to obtain interesting results on the double-mode Cepheid EW Set (Figer et al., 1991), on the Be star OT Gem (Arellano Ferro et al., 1998) and on the eclipsing binary V753 Cyg (Beltraminelli et al., 2000). More recently, several GEOS members have started collecting a large sample of times of maximum brightness of RR Lyr stars in order to build-up a database as extensive as possible. Such a database is decribed below together with the results of a campaign on RR Lyr itself.

This star’s variation was discovered photographically by Romano in 1957. It was included in the GCVS in 1978 as PXCep, and I started to observe it in 1983.The star is usually at maximum, but on several occasions I was able to observe either a rise or the start of a fall. Finally on 1984 October 21, the first minimum was observed, and then a second one ten days later.The star’s constant behavior, outside the minima, indicated that is was an EA type of eclipsing binary. The amplitude of the eclipses is about 2.6 mag. Secondary minimum therefore has an amplitude of 0.11 mag., which is undetectable visually.

The 1986 Minor Planet Ephemerides call observers' attention to the need for astrometric observations of 120 objects on the "critical list". Their magnitudes are generally between 15 and 18 at opposition. The author's programme of observation with simple means was described. The equipment used was a Newtonian 41-cm, f/4.8 reflector, a standard camera back, and Kodak TP2415 film, hypersensitized in forming gas. Out of 25 observations attempted, 20 photographs were obtained, 8 of which were of sufficient quality for the positions to be measured and to be published in Minor Planet Circulars. On two photographs, the minor planet (1982KM) was detected, but there were no suitable reference stars within the field. (The lack of reference stars brighter than mag. 10 in certain regions should be noted.) The return of measured positions versus photographs obtained (40%)

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