There is NO prohibition against homework questions here at Astronomy. StephenG's comment that he was voting to close for suspicion of homework was ill-advised and had no basis in site policy.
JanDoggen then made reference to "some guidelines across the network" but this is a red herring. Most experienced users will be aware that each SE site is at liberty to define its own rules for what's on-topic. For example, homework questions are explicitly permitted on Physics.SE, and that meta post provides guidelines for how they should be asked (and links directly from their on-topic page.
Another example is English Language & Usage, which gets more questions in 12 hrs than Astronomy gets in a week. They too have no official site ban on homework questions, and their meta post How to deal with homework questions provides a very balanced and informative perspective based on two principles:
- It is okay to ask about homework, and
- An answer that doesn't help the student learn is not in their own
In fact, that EL&U meta post is mostly based on a similar post on SO Meta. So Jan, it looks like there are popular, high-traffic SE sites that cautiously accept homework questions.
I think this specific issue touches on a broader problem here on Astronomy. I've previously posted here because of some users' excessive eagerness to close questions as "off-topic" when they're nothing of the sort - they're merely poorly researched, overly basic or just plain low-quality. But as uhoh rightly points out, some are low-quality simply through a combination of inexperience on our site and the lack of a post-grad; a bit of tolerance (and assistance) might be a good thing.
I'm probably a bit quick on downvotes here, and perhaps I too need to be a bit more tolerant. But a downvote, while disheartening to the receiver, is I think far less affronting than having their question closed, especially when the question is on-topic but is being closed as purportedly "off-topic". I think it's worthwhile reminding ourselves (and especially reminding those of us who tend to forget) that SE's philosophy is to encourage answers rather than eliminating the questions.
Let me quote from SO Blog's Respect the community – your own, and others’:
[closing] should be your last resort. Close questions with an eye
toward improvement and re-opening, not driving users away.