  We discuss an effect of the intergalactic absorption of the TeV gamma-rays in
time-averaged spectrum of Mkn 501 measured by the HEGRA Collaboration. Analysis
of the spectral behavior, variability time scale and relevant calculations of
TeV gamma-ray emission allow to conclude the presence of a noticeable
absorption of the TeV gamma-rays in the Mkn 501 energy spectrum.

Astrophysics