When someone asks a question which folks are likely to ask over and over, you should use that opportunity to create a really awesome, canonical answer to make this an invaluable resource on the Internet.
For example, if someone were to ask when the sun/moon rise/set on a given date, don't give them the time or answer with a hyperlink to some other discussion group somewhere. Write a detailed, step-by-step, ultra-clear guide with screenshots and examples. Really teach folks looking for that information how to find or derive that information for themselves.
That's how you build up a body of answers to common questions in Astronomy. Those questions will bring in lots of traffic from search engines. And if you can provide great answers to those questions, you stand a great chance of attracting some great new users who will add value for years to come.
You can't really do that with a single page with a list of links.