I am hung up on these observatory closings.
Could one do FISA surveillance from one of these places...
All that data is continuously collected by multiple other systems, the FISA part of it is allowing the unmasking of heretofore unknown names because they are associated with people in the warrant that are surveilled as well.
You have huge amounts of data that is then analyzed and correlated into an intelligence product centered around the individuals named in the warrant. What they wanted was the President's campaign as a whole. And they got to look at all those people as well because of their association to the plants.
The "eyes" of an observatory are exclusively on outer space, not useful for anything ground-based.
Because it has to transfer immense digital data to researchers elsewhere, an observatory will have very high-bandwidth access to the internet, so it would be a good place for a janitor to do his dirty downloads.
Closing the post office does seem a little weird, unless they were looking for suspicious and related postal deliveries. Another possibility is that the same cleaning company (owned by the parents of the janitor) had the contract for the post office as well as the observatory. The feds surreptitiously nabbed the janitor's laptop. When he noticed, he went on a tirade about lax security at the lab, and that there might be a serial killer on the loose.
Sunspot, NM is a very small town -- basically just the people who work at the observatory (40-50 houses, based on satellite imagery). Closing the post office probably had less impact on the townspeople than shutting down their high-speed internet access through the lab.