A question I asked has been closed by a moderator as an off-topic homework-like question, although it is clearly not a homework question.
Why was it closed as being homework-like?
The reason I closed this as being homework-like is that:
It also seems like an unusual question for a person to come up with on their own. The question doesn't include any justification for why you wanted to ask it, which could be a plausible explanation of how you would come up with this question other than from a homework assignment or educational exercise.
I see that in the comments, you mentioned "Additionally, I would like to know how people in earlier times knew this fact without having access to modern equipment, including telescopes." It's a minor factor but that would have been a good thing to add to the question to make it seem marginally less homework-like (though I'm not saying that I necessarily would have chosen to leave the question open if you had added that).
Now, none of that is conclusive evidence that your question should be put on hold as homework-like, but putting all the factors together, it does make it look rather suspicious. The final thing about this question in particular is that it was accumulating a lot of upvotes and had been added to the Hot Network Questions list. Questions on HNQ get a lot more exposure a lot more quickly, and when they have issues, they call for quicker action. So I decided to put the question on hold right away. There's an argument that maybe I should have just removed the question from HNQ while leaving it open, but I thought about it and decided that I was confident enough that the question fits our definition of a homework-like question that I might as well just put it on hold.
Of course, sometimes acting quickly on HNQ's leads to a mistake (not that I'm saying I made a mistake here, but it's generally understood that moderator actions won't be correct 100% of the time). But closing a question, if done by mistake, is relatively easy to fix.
To head off one possible objection, note that I've deliberately avoided saying that your question is a homework question. I don't know whether it really is a homework question or not, but in the form you posted it, it has enough characteristics that I've found to be associated with homework questions that I thought it should fall under our policy for them.
So I agree that this is not a homework/check-my-work question, but I can see why someone would think that it is based on DavidZ's response.
Additionally, after thinking about it further, I think the question should remain closed. It seems to fall into the "engineering" category, where the close banner reads
This question appears to be about engineering, which is the application of scientific knowledge to construct a solution to solve a specific problem. As such, it is off topic for this site, which deals with the science, whether theoretical or experimental, of how the natural world works.
Your question isn't really asking about the underlying physics principles, even though the topic in general involves physics principles.