  We present the first direct excitation of the presumably ultra-narrow $1001
\, \textrm{nm}$ ground state transition in atomic dysproium. By using resonance
ionization spectroscopy with pulsed Ti:sapphire lasers at a hot cavity laser
ion source, we were able to measure the isotopic shifts in the $1001 \,
\textrm{nm}$ line between all seven stable isotopes. Furthermore, we determined
the upper level energy from the atomic transition frequency of the $^{164}
\textrm{Dy}$ isotope as $9991.004(1) \, \textrm{cm}^{-1}$ and confirm the level
energy listed in the NIST database. Since a sufficiently narrow natural
linewidth is an essential prerequisite for high precision spectroscopic
investigations for fundamental questions we furthermore determined a lower
limit of $2.9(1) \, \mu\textrm{s}$ for the lifetime of the excited state.
