Global survey of star clusters in the Milky Way I. The pipeline and
  fundamental parameters in the second quadrant
  Aims: On the basis of the PPMXL star catalogue we performed a survey of star
clusters in the second quadrant of the Milky Way. Methods: From the PPMXL
catalogue of positions and proper motions we took the subset of stars with
near-infrared photometry from 2MASS and added the remaining 2MASS stars without
proper motions (called 2MAst, i.e. 2MASS with astrometry). We developed a
data-processing pipeline including interactive human control of a standardised
set of multi-dimensional diagrams to determine kinematic and photometric
membership probabilities for stars in a cluster region. The pipeline
simultaneously produced the astrophysical parameters of a cluster. From
literature we compiled a target list of presently known open and globular
clusters, cluster candidates, associations, and moving groups. From established
member stars we derived spatial parameters (coordinates of centres and radii of
the main morphological parts of clusters) and cluster kinematics (average
proper motions and sometimes radial velocities). For distance, reddening, and
age determination we used specific sets of theoretical isochrones. Tidal
parameters were obtained by a fit of three-parameter King profiles to the
observed density distributions of members. Results: We investigated all 871
objects in the 2nd Galactic quadrant, of which we successfully treated 642 open
clusters, 2 globular clusters, and 8 stellar associations. The remaining 219
objects (24%) were recognised by us to be nonexistent clusters, duplicate
entries, or clusters too faint for 2MAst. We found that our sample is complete
in the 2nd quadrant up to a distance of 2 kpc, where the average surface
density is 94 clusters per kpc$^{2}$. Compared with literature values we found
good agreement in spatial and kinematic data, as well as for optical distances
and reddening. Small, but systematic offsets were detected in the age
determination.
