  The article presents the results of a study of the design features of
vertical and L-shaped ancient Egyptian sundials, developed their models, on the
basis of which the reconstruction of the sundial was carried out. An original
scheme of a simple method for a fairly accurate time measurement with their
help is also proposed. The model proposed by us, which describes a vertical
sundial, is a vertical sundial with an inclined gnomon that takes into account
the latitude of the area. The model proposed by us is characterized by marking
the hour lines from 6 to 12 o'clock every hour. From 12:00 a shift is made in
the marking of the hour lines for half an hour, and then the marking is
repeated every hour. As a consequence of the reconstruction of the vertical
sundial, we have developed and proposed a model that describes the design
features and operation of two types of L-shaped sundial. They had to work in
conjunction with an inclined gnomon, like a vertical sundial, or directly with
a vertical sundial. In this case, the L-shaped sundial could complement the
vertical sundial by providing the ability to read hour markers and interpret
the readings of the vertical sundial, as there were no inscriptions on the
vertical sundial. The article also provides a decoding of the inscription from
the tomb of Seti I, which has long intrigued researchers. It is proved that the
inscription contains the lengths of the intervals between adjacent marks of the
L-shaped sundial of the second type, where the first interval corresponds not
to one hour, but to half an hour.
