As you mention ‘a morning star’, here is a collection of expressions and ways of denoting different times of day when writing:
In the midnight hour. Poetic, and from a song. Around midnight.
During the hours of darkness. Or during daylight. After dark. Or, before dark. While it’s dark.
Before noon. Before midday.
When it’s light. When it’s dark. When it gets dark.
As darkness falls. At nightfall.
As the street-lamps come on. Before the dawn.
At morningtide. At eventide. (archaic - can be used poetically).
Before the sun is over the yard-arm (that’s before noon, after which, having an alcoholic drink is sanctioned or allowed). It means morning, before noon. But note that is usually used in the context of being able to have an alcoholic drink. Eg ‘the sun was over the yard-arm so they headed to a nearby bar for a drink.’ (Archaic, nautical, collonial yet still in use).
At sunrise. After sunrise. After the sun comes up. When day begins. As day begins. When the sun comes up.
At sunset, after sunset. As the sun sets. Around sunset. As the sun goes down. After sundown.
Once the moon rises (eg - once the moon rises, party-goers dance the night away). When the moon is in the sky. When the moon is shining.
At sun-up. At day-break. (Means dawn or sun-rise) after day-break.
At dawn. When the light dawns.
While the sun is in the sky.
When the sun is high in the sky (like, noon til 3pm).
When the sun reaches its summit. When the moon reaches its zenith.
The small hours. The wee small hours of the morning. (Like 1, 2,3am)
From dusk to dawn (all night - from when it gets dark until the sun comes up).
At dusk. At twilight. (When it starts to get dark - in-between day and night). Around twilight. This is ‘crepuscular’.
The witching hour (midnight - use in context of say, Halloween or spooky story). Around the witching hour. Means around midnight.
When the stars come out. When the stars may be seen. As the stars are shining.
As the moon sets. As the moon goes down. (Less often used - poetic).
Noontime. Lunchtime. Around lunchtime.
Dinnertime. Around dinnertime. (Time varies from 6-8pm or can be 12-2pm depending on location). After dinner.
Matitudinal: Adjective. of or occurring in the morning.
Between lunch and tea-time (between aboutt 12 noon and 4pm, UK).
Between breakfast and lunch. ie - that’s morning.
Suppertime, around suppertime (about 8pm, archaic, poetic).
After dinner, after lunch, after breakfast. Eg ‘after polishing off his bacon and eggs, he... (UK, where eggs and bacon are a common breakfast food).
At teatime (4pm but varies).
As the sun goes to bed. As the moon begins to rest it’s weary head.
As the sun sleeps (eg. As the sun sleeps, merry-makers dance the night away in the hot tropical streets).
Suggested listening ‘a lullaby of Broadway’ - song - it has a lot of these kind of expressions in it.