  The definition of well-behaved coordinate charts for black hole spacetimes
can be tricky, as they can lead for example to either unphysical coordinate
singularities in the metric (e.g. $r=2M$ in the Schwarzschild black hole) or to
an implicit dependence of the chosen coordinate to physical relevant
coordinates (e.g. the dependence of the null coordinates in the Kruskal
metric). Here we discuss two approaches for coordinate choices in spherical
symmetry allowing us to discuss explicitly "solitary" and spherically symmetric
black holes from a regular horizon to null infinity. The first approach relies
on a construction of a regular null coordinate (where regular is meant as being
defined from the horizon to null infinity) given an explicit solution of the
Einstein-matter equations. The second approach is based on an affine-null
formulation of the Einstein equations and the respective characteristic initial
value problem. In particular, we present a derivation of the
Reissner-Nordstr\"om black holes expressed in terms of these regular
coordinates.
