On the morning of the International Society for Astrological Research’s Certification of Astrological Proficiency (ISAR CAP) exam, which was held at a Marriott in Chicago on a balmy morning in May, the cosmic weather boded well. The moon was in Sagittarius, the most erudite of the signs, and the communication planet Mercury had just entered quick-witted Gemini. There had been a dramatic full moon the night before , but the handful of astrologers who’d signed up to take the test didn’t seem too shaken by it. They were, after all, professionals — or at least, hoping to be, having undergone years of intense preparations for this six-hour “metaphysical SAT,” as one called it. Though technically open book, the ISAR CAP has a reputation for being one of the most grueling exams in the astrological field.

Yes. In 2018 there are multiple rigorous exams that assess one’s ability to read the stars.

And yes, it may seem strange to apply extremely technical standards to this abstract spiritual practice, but doing so isn’t without precedent. Astrology has existed, in some form, since at least ancient Babylonian times and was long considered a completely logical means of making sense of the world. It wasn’t until rationalism became all the rage in the 19th century that astrology was relegated to the realm of the mystical and absurd.

Today, it’s mostly considered the province of women’s magazines and Instagram memes, at best a harmless fiction and at worst a pernicious pseudoscience. But for a rising number of students and specialists, the practice is extremely serious, if admittedly unscientific.