SHA Septimius Severus III.9:
He had meanwhile lost his wife, and now, wishing to take another, he made inquiries about the horoscopes of marriageable women, being himself no mean astrologer; and when he learned that there was a woman in Syria whose horoscope predicted that she would wed a king (I mean Julia, of course), he sought her for his wife, and through the mediation of his friends secured her. (Loeb trans.)
SHA Antoninus Geta III.1:
...Julia, whom Severus married because he found out that her horoscope showed that she should be the wife of a king, while he was still only a subject, though he held even then an excellent place in the state. (Loeb trans.)
SHA Geta II.6-9:
With regard to this same Geta, Severus, on learning his horoscope -- a study in which, like most Africans, he was very proficient -- is said to have made the remark: "It seems to me strange, my dear Juvenalis, that our Geta is destined to be a deified emperor, for in his horoscope I see nothing imperial." Now Juvenalis was his prefect of the guard. And Severus was not mistaken. For when Bassianus had killed Geta and was in fear of being branded as a tyrant because of his act of fratricide, he was told that his crime could be mitigated were he to give his brother the appellation of the Deified; he then remarked, it is said, "Let him be deified provided he is not alive." Accordingly, he placed him among the deified emperors and so came back into favor with a good reputation, fratricide though he was. (Loeb trans.)
SHA Septimius Severus 4.2-4:
Next he ruled Pannonia with proconsular powers, and after this he drew in the allotment the proconsular province of Sicily. At Rome, meanwhile, he was presented with a second son.
While he was in Sicily he was indicted for consulting about the imperial dignity with seers and astrologers, but, because Commodus was now beginning to be detested, he was acquitted by the prefects of the guard to whom he had been handed over for trial, while his accuser was crucified.
He now served his first consulship... an office to which Commodus appointed him from among a large number of aspirants. (Loeb trans.)
SHA Septimius Severus XV.4-5:
In the meantime, on the advice of Plautianus, he hunted down the last survivors of Pescennius' revolt, and he even went so far as to bring charges against several of his own friends on the ground that they were plotting to kill him.  He put numerous others to death on the charge of having asked Chaldaeans or soothsayers [vates] how long he was destined to live; and he was especially suspicious of anyone who seemed qualified for the imperial power, for his sons were still very young, and he believed or had heard that this fact was being observed by those who were seeking omens regarding their own prospects of the throne. (Loeb trans.)