Harakhti was an Egyptian god of the morning. His name means "Horus of the Horizon," meaning that he ruled over the horizon in the same manner in which the god Horus was said to have ruled over Egypt as the first Pharoah after Osiris. Harakhti is sometimes seen as an alternate manifestation of Horus, rather in the same manner that the Christian trinity represents three separate aspects and persons of the same divinity. However, in the city of Heliopolis and a few other places Harakhti and the sun god Re blended together to form a single amalgamation that went by the name Re-Harakhti.
It was said that the Pharoah was born on the eastern horizon as Harakhti and that his rule over both horizons was related to this fact. Harakhti was depicted in art as a falcon-headed guy, although Re-Harakhti appears to have been a bit more common in art, especially in royal tombs. The latter deity was the same in appearance except for the addition of a large orb over the head, intended to represent the sun.
The name Harakhti was also associated with the worship of the actual, physical sun (as opposed to a sun god of some sort) that arose around the rule of Amenhotep III. The sun in this form was most commonly called Aten, and its worship came into direct competition with another god called Amun, with whose statue the Pharoahs were sometimes expected to consult. Amenhotep III eventually wound up siding with the worshippers of Aten/Harakhti, and he changed his name to Akhenaten to reflect this change, which was supposed to have been one of the biggest in the long history of Egyptian religion. It didn't take, though. After Akhenaten's death, sun worship fell out of favor and Harakhti became associated with more orthodox Egyptian gods like Horus, Re, and to a lesser extent Osiris.