A&A Supplement series, Vol. 122, April II 1997, 201-213
Received March 20; accepted April 22, 1996
C. Motch 
- P. Guillout 
- F. Haberl 
- M.W. Pakull 
- W. Pietsch 
- K. Reinsch 
Send offprint request: C. Motch
Observatoire Astronomique, UA 1280 CNRS, 11 rue de l'Université,
F-67000 Strasbourg, France
Max-Planck-Institut für Extraterrestrische Physik, D-85740,
Garching bei München, Germany
Sternwarte, Geismarlandstrasse 11, D-37083, Göttingen, Germany
The analysis of the part of the ROSAT all-sky survey covering the galactic plane is
the scope of a dedicated project called the ROSAT Galactic Plane Survey. In order to
statistically understand the nature of the 
14 000 sources discovered by
ROSAT at |b| 
20
, a number of sample areas have been chosen for
follow-up optical identification. In this paper we present the X-ray and optical
material gathered in a region located in the Cygnus constellation, centered at l
= 90
, b = 0
and covering an area of 64.5deg
. A total
of 95 and 128 sources are detected with a maximum likelihood larger than 10 and 8
respectively. With a typical survey exposure time of the order of 700 to 900s
the flux completeness level is 
0.02 cts s
corresponding to 
2
10
erg cm
s
. The position of the sample area allows to investigate the
soft X-ray content of a rather typical region of the galactic plane. In this
paper we describe the details of the observational procedures and data reduction.
For each ROSAT source we list the main X-ray characteristics together with those
of the proposed optical identification. When appropriate, we also show optical
spectra and finding charts. The full analysis and discussion of these data are
presented in a companion paper (Motch et al. 1997).
keywords: X-ray general, X-ray stars, stars: activity, stars: neutron, stars: statistics