What the hell is going on at the Naval Observatory?

Maurene Dowd's column in the New York Times pointed out that on Google Earth, the Naval Observatory, residence of the Vice President, is shown as a blurry blob. Apparently this used to be true of a lot of buildings in DC, but Google found alternate sources for images of the White House and other buildings, which are perfectly clear. Only the Naval Observatory remains a pixelated blur.

I went to Google Earth and to verify this, and also noted that they don't even tell you the address. If you type in "Naval Observatory" it takes you to some generic DC location. You have to follow Massachusetts Avenue northwest from Dupont Circle to the giant circular blob which is the observatory grounds. (I used to take walks up to the observatory when I worked on Dupont Circle, so it's a familiar route).

Not only that, but MSN's virtual earth shows the same blob!

I'm guessing that they've installed some sort of anti-aircraft facilities there and they don't want them seen.

My other conclusion is that MSN Virtual Earth, comparatively speaking, sucks bigtime! I had to download software for Google Earth, but it's so much slicker, I don't mind.