first light vs morning

first light

• The time when light first appears in the morning; dawn, especially the start of dawn. 

• The first use of a telescope or other instrument to capture an astronomical image. 

morning

• The early part of the day, especially from dawn to noon. 

• The first alcoholic drink of the day; a morning draught. 

• The early part of anything. 

• A greeting said in the morning; shortening of good morning