Observatories

[speedbird2]

Excuse me if I am posting this in the wrong place but I have a comment regarding the observatory at the Burj Khalifa in Dubai. The observatory, named At the Top, is poorly named since the deck is actually on the 123rd/124th floors of this 163 storied building. Strangely, the observatory is about 1,239 feet from the top. Its level is 1483 from the street. My question is why wasn't the observatory built at a higher level. Is there a technical explanation? It seems that most observatories are located just under the spire.