  In experimental nuclear astrophysics it is common knowledge that reaction
cross sections must be measured in the astrophysically relevant, low energy
ranges or at least as close to them as possible. In most of the cases, however,
it is impossible to reach such low energies. The reactions must therefore be
studied at higher energies and the cross sections must be extrapolated to lower
ones. In this paper the importance of cross section measurements in wide energy
ranges are emphasized and a few examples are shown from the areas of hydrogen
burning processes and heavy element nucleosynthesis.
