The builder of this particular observatory, Tyrass is a gold dragon who has grown weary of interruptions to his work. True, intruders only find their way to his observatory once or twice a decade, but to a creature as old as Tyrass, such frequency is downright infuriating. In years past, the dragon was relatively polite to nonviolent visitors, and as a result, tales of his willingness to provide information might still be circulated among the lesser races. Over the last twenty years, however, he has become notably harsher when dealing with strangers, and will often determine whether they have any shred of valuable information (and thus might be worth momentarily sparing) long before they ever reach the observatory itself.
However, Tyrass is not always home. Being particularly interested in planar phenomena, the dragon often takes trips to other planes, sometimes for months at a time. He also sometimes visits other Siberys observatories for corroboration of particularly momentous discoveries, though these trips last only a few days at most. (Conversely, very unlucky adventurers might arrive at the observatory on a day when Tyrass is entertaining a council of dragons from these other observatories.)