What Latvian deity ranks just below the solar goddess of Latvian mythology in popularity?
Auseklis: Auseklis (derived from root "aus-" - "dawn") was a Latvian god, and the personification of the celestial body Venus. Auseklis:  He is the third most popular deity in Latvian mythology after Saulė and Mēness, but is almost exclusively mentioned in folk songs. Saulė: Saulė (Lithuanian: "Saulė" , Latvian: "Saule" ) is a solar goddess, the common Baltic solar deity in the Lithuanian and Latvian mythologies.
Auseklis