mastaba orientation and Akhet

Quoting Wikipedia:

Akhet is an Egyptian hieroglyph that represents the sun rising over a mountain. It is translated as "horizon" or "the place in the sky where the sun rises".

Akhet appears in the Egyptian name for the Great Pyramid of Giza (Akhet Khufu) and in the assumed name of Akhetaten, the city founded by pharaoh Akhenaten. It also appears in the name of the syncretized form of Ra and Horus, Ra-Horakhty (Ra–Horus of the Horizons).

photo taken on September Equinox at Thebes:

Projecting the geography of Boeotia on to Giza. Thebes is the apex of Khufu's pyramid. The scaling factor is taken as the same one used to map the three Hellenic mountains on to the three Giza pyramids.

The direction between the two mountain peaks of Helicon align with the orientation of Hemiunu's mastaba.