Revised distances to several Bok globules
  Distances to Bok globules and small dark nebulae are important for a variety
of reasons. We provide new distance estimates to several small clouds, some of
them known to harbor YSO and molecular outflows, and thus being of particular
interest. We use a procedure based on extinctions determined from the (H-K) vs.
(J-H) diagram, and stellar distances based on a Hipparcos calibration of the
main sequence locus: $M_J[(J-K)_0]$. The cloud confinement on the sky is
determined from contours of the average (H-K) color formed in reseaus. Along
the sight line stars affected by the clouds extinction may be extracted from
the variation of the number density of atomic hydrogen $n_H\sim
A_{V,\star}/D_\star$ to provide the cloud distance and its uncertainty.
According to our estimates, the group of three globules CB24, CB25 and CB26 is
located at 407+/-27 pc, farther than the previous estimates. CB245 and CB246
are found at 272+/-20 pc, suggesting that the current distance to these clouds
is underestimated. Toward CB244 we detect a layer at 149+/-16 pc and the cloud
at 352+/-18, in good agreement with previous studies. CB52 and CB54, though to
be at 1500 pc, are found at 421+/-28 pc and slightly beyond 1000 pc,
respectively. It seems that the most distant Bok globule known, CB3, is located
at about 1400 pc, also significantly closer than currently accepted.
