  In this work we consider some old hypotheses according to which remarkable
mesolithic village Lepenski Vir (9500 -- 5500 BC) at the right (nearly west)
Danube riverside in the Iron gate in Serbia was an ancient (one of the oldest)
Sun observatory. We use method recently suggested by A. C. Sparavigna,
concretely we use "freely available software" or local Sun radiation direction
simulation computer programs. In this way we obtain and discuss pictures of the
sunrise in the Lepenski Vir during winter and summer solstice and spring and
autumn equinox in relation to position of the mountains, especially Treskavac
(Trescovat) and Kukuvija at left (nearly east) Danube riverside (in Romania).
While mountain Kukuvija represents really the marker for the Sun in date of the
winter solstice, mountain Treskavac, in despite to usual opinions, does not
represent a real marker for the Sun in date of the summer solstice. Sun rises
behind Treskavac, roughly speaking, between 22.April and 1. May. It corresponds
to year period when heliacal rising of the Pleiades constellation occurs, which
by many ancient cultures, e.g. Celts of northern Europe, denotes very beginning
of the year. All this, in common with some archeological facts (house-shrine
No.47 in the Lepenski Vir holds seven signs beside hearth which would
correspond to the seven Pleiades stars), opens a possibility that Lepenski Vir
was an ancient Pleiades constellation observatory.
