φάσμα

The appearance of a star can be meant in various ways: typically, it refers to observations in twilight but there are appearances in the evening and appearances in the morning.

The photograph on the left shows Venus short above the mountain in the morning twilight. The Pleiades are a bit higher where the sky is slightly darker which makes it sufficient to recognize the fainter stars. However, both are really difficult to see and this is because of their appearance in the (bright) twilight. The form of appearance is called the "heliacal rising" if it happens for the first time in the year.