With no explanation, label each line with "O", "other-astronomything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
This
led
to
considerable
interest
in
61
Cygni
by
contemporary
astronomers
,
and
its
continual
observation
since
that
date
.
This:O
led:O
to:O
considerable:O
interest:O
in:O
61:other-astronomything
Cygni:other-astronomything
by:O
contemporary:O
astronomers:O
,:O
and:O
its:O
continual:O
observation:O
since:O
that:O
date:O
.:O