how many Luxury for an Observatory?

[FWCain]

Considering that an observatory needs large lenses and a large mirror, I was thinking that an Observatory as a Civic Structure would need a relatively large amount of Luxury commodities.

Here's what I came up with:

Observatory
7
Bldg.
1x1 (1)
12 RP
6 Lumber, 8 Luxury, 6 Stone
Scholarship (expert)
DC 23
+1 to Prognostication and Recover Army (Lost)

Does this sound about right to you?

What about the traits Edifice and Famous? Either? Both?

Thanks,
Franklin