Water vapour emission in ON2 is associated with interstellar masers in a
region of active star formation in the dust-gas cloud complex Cygnus X
(Johnston et al. 1973). The main 
maser source in ON2
(the northern one) is located near a compact HII region (Matthews et al.
1973; Harris 1976; Matthews & Spoelstra
1983) and consists of two spatially separated regions, which are
located on the opposite sides of a shell (Walker et al. 1978)
whose diameter is about 2.7 1015 cm.
According to recent VLBI observations, the main maser is composed
of three groups of features, located in a volume with diameter about
4 1016 cm (Hofner & Churchwell 1996). The maser is
situated about 0.04 pc in front of the "cometary" ultracompact HII region
.
From regular observations of the maser emission at 22 GHz made since 1981 it is found that there is: 1) anticorrelation between the integrated fluxes of two groups of spectral features (Lekht et al. 1996) and 2) velocity drift of the centroid velocity of each group (Márquez & Lekht 1997). The observed velocity drift may be caused by luminosity variations of the central star. However, we cannot exclude the possibility that other factors, related with the process of star formation in the ON2 region (Márquez & Lekht 1997), may exert an influence on the maser.
In the present work we continue the study of the maser sources in
ON2 made earlier by Lekht et al. (1996). In that work the spectra obtained with the Pushchino RT-22 radio telescope (Russia)
during 1981-1995 were presented and a detailed analysis of the time
variation of the integrated emission and velocity centroid were
made. The aim of the present work is to study the variations of individual
spectral features: their flux, radial velocity and line widths. The results
of our latest observations during December 1995-July 1996 with the RT-22
radio telescope at Pushchino are also included.