I would think those are fair game, but a shot opposite the sun of a person or object that’s just lit up all golden from the setting sun wouldn’t really count in my mind, if that’s where monsieurstabby was going. orionid can clarify though.
So orionid, would you count this as ok? or no. The tree kind of ends up the subject over the sky, but it’s obvious it was taken during sunset with those colors so I’m not sure how much wiggle room you’re giving 🙂