Look up twilight definitions and you get something like this https://www.weather.gov/lmk/twilight-types#:~:text=Astronomical%20Twilight%3A,urban%20or%20suburban%20light%20pollution.

The afternoon events come earlier as we approach the winter solstice and later as we approach the summer solstice. Generally speaking, you can start alignments during civil twilight or sooner. If you can see a star, you're good to go.

Viewing DSOs can start usually around nautical twilight when it's gets dark. Then Astronomical twilight is the period where the sky is darkest.

If you go to this site https://www.timeanddate.com/sun/ and enter your location, it will give you the time frames for solar events.