Comparing it to Space Exploration that is merely 2 and a half months ahead in its beta days to Astronomy SE, I can say that you've gathered more questions and answers than we did at the edge to going public. But I see Astronomy developing more early days problems, so I can see the need to perhaps accelerate the pro tempore moderator selection process. Some of the problems here that I didn't see as apparent on Space.SE:
- Plagiarism and attempts at creating canonical Q&A early on
- Scope interfering with scopes of other SE sites, with opposition from the latter
- Greater number of inexperienced SE members that need guidance
- The majority of questions still seem to be of the general reference Q&A kind
- Private beta members are less active in meta, with not many discussions active
But don't get me wrong, all of these points can be worked on and will be a lot easier to achieve once you get your own moderators. They will have quite a bit of work in the early days, but this workload does decrease as the community itself learns the ropes and the site has more high reputation users.
As far as the community goes, I'd say you're in slight advantage to where we were during the private beta, largely probably due to some of our Space Exploration regulars moving here and with clear intentions in making Astronomy (2.0, reboot?) work this time around. My suggestion to kickstart it would be in also tapping from external to SE experts, get some fresh but highly qualified names here to establish more authoritative presence. Depending on SE community alone is, in my opinion, not the best option with the nature of the site being so far away in scope from the ability of your average tech geek (myself included, no disrespect intended) that is lurking the seas of Stack Exchange to keep threads interesting and insightful.
Oh, and it is also by far too early to be looking at Area 51 statistics. With merely a week on your tachometer, those stats are not the best indication of how well the site is progressing. What you want is quality. Quality that will reassure each of your members it's not wrong to suggest this website to some of their friends and not merely be seen as spamming their inboxes.
Once publicly available stats will start making sense, you will be able to somewhat track them on Quantcast. For the time being though, they are utterly irrelevant and not worth preoccupying yourself with them.
My 2 cents. ;)