EVE Fiction

That could be one reason for them, but in the older lore I've read the Jove crave most of all, knowledge. Supposedly they had taps on everything happening in the cluster, probably because of these observatories. Also militarily, Jove are the weakest race - while their tech is advanced, their small number would spell doom for them if even say, two empires decided to attack them. Thus their greatest weapon was and is espionage and information warfare - they'd prefer to win battles before they even happen.

As others have deduced before me, the observatories seem to be left from their glory days, possibly the Second Empire, suggested by the fact that most commonly they seem to be found in and near Angel NPC Space, which is known to have been the site of the original Jove Empire and that the observatories bear little resemblance to any known modern day Jove vessels or stations. Again returning to your post, indeed the observatories could have played some part in the fight against the Jovian Disease, but when they were presumably constructed, I think none of the four empires were even capable of space flight and capsuleers have been around for around a hundred years in a rudimentary form and as the current demigods of sorts little over a decade.

Undoubtedly, the Sleepers play some apparent part in the grand scheme of things and my best guess is that the observatories were either seeking the Sleepers or Talocan, or were meant to help protect Jove from the Sleepers.

Unfortunately, my knowledge is spotty at best, but my two cents.