Astrology

Sourcing & Approach

♑ Modern Study ♑ Vedic Reference ♑ Lilly Reference ♑ Agrippa Reference ♑ Sky Mapping Reader

Astrology is an interesting section. I originally intended this to be a resource for practitioners to check the influences of the sky on their magical work. This quickly became difficult, as you may imagine. I began with modern astrology, in my naivety thinking this to be the most accurate. The Modern section of the resource is a culmination of teachings and courses I took to explain the attributes of houses, planets, and zodiac signs. This was my introduction to the topic. When I started to peel back the layers toward their origins, it became clear that there are competing understandings, and multiple traditions, each with deep roots that needed to be respected and presented on their own terms. This line of thought brought me to a nexus of paths, but I took the strongest ones and landed on 3 root traditions: Lilly, Vedic, and Agrippa.

Vedic is not an author, unlike the other two, and it's also the tradition I came to with the least familiarity. Vedic astrology is still largely a moving piece for me. I expect to update this section multiple times as my understanding deepens. I know nothing of India, Tantra, yoga, or their deities and rituals, which meant I couldn't start from a foundation the way I could with the other traditions. For now, the information I gathered comes from Varāhamihira's Bṛhat Jātaka and standard BPHS (Vedic), since this was open to the public as another ancient text. This appeared to be the strongest source of original truth I was able to find, but not speaking the language, I needed to use a translation. (source)

Lillian astrology was much more straightforward for me. His manuscript Christian Astrology, while written in 1647, was much easier for me to understand. It's from here that much of modern astrology pulls from, with explanations of the houses of the sky, the planets, the zodiac, and correspondences like modality, element, physical traits, and behaviors. Lilly explained how to manually chart the sky and use essential dignities to describe their influences on the house, the zodiac, and each other. This essentially became the modern horoscope and birth chart we know and use today in Western countries.

Agrippan astrology was much more in line with my original outset for this resource. It provides the planetary harmonies (metals, birds, stones, body parts), associations to Hebrew names and sephira, and magical usefulness by describing what each planet helps or hinders in magical works. This includes magical squares and what amplifies or diminishes their influences, letting the practitioner use this to empower or weaken certain preferred outcomes. I chose to put Agrippa behind the paywall, because it's the tier most specific to practitioners rather than diviners. Useful for some, but it would clutter the experience for the general user who's only looking to understand modern astrology's roots in Lilly and Vedic tradition.

The astrology calculator is a unique piece of code. I want to be upfront about why it isn't built on the Swiss Ephemeris, the standard most professional astrology software uses, and what that means for accuracy. I built the calculator from scratch, using published public-domain astronomical theory rather than Swiss Ephemeris code or data. The positions come from Meeus's solar and lunar series and JPL's Keplerian planetary elements, with the houses computed from standard Placidus math, plus Whole Sign, Equal, and Porphyry as options. In practice this means very good, but not research-grade, accuracy. The Sun is accurate to under 36 arcseconds, the Moon to about 10, Mercury/Venus/Mars to about an arcminute, and Jupiter/Saturn to about 10 arcminutes. Chiron is a rougher two-body approximation, good to about a degree. I validated it against real sky events, like the 2020 and 2024 solar eclipses and the 2020 Jupiter-Saturn conjunction, and it landed within a few arcminutes of the historical record each time. It's built for charts from roughly 1800 to 2050, using tropical, geocentric positions, which covers the vast majority of natal work. For most practitioners, this is more than close enough for real chart reading. If you need research-grade precision for technical or academic work, that's the one case where I'd point you toward professional software built on Swiss Ephemeris directly rather than this tool. That said, it's a reliable tool for identifying the current position of the celestial objects, and their influence can be measured for natal chart reading and for magical purposes. The calculator can be pushed to the chart reading page for a full view of where things sit, and individual items can be studied on their own as well. It only outputs structural positions, signs, houses, and aspects; the interpretive meanings you'll find elsewhere on the site are the Guidebook's own. This also feeds the Agrippan spell helper feature, which reads the influence of current astrology on the practitioner's magical efforts and suggests ways to strengthen it.

As with all information presented here, this is not meant to be a strict and unassailable presentation of truth, but rather a realistic and hopefully mostly unbiased presentation of information for the use of students and practitioners. Please meditate upon that which aligns with your practice, and adjust to your personal preferences if misalignment is identified. I also invite criticism and good faith knowledge sharing. If you want to provide me with an improvement to the accuracy of the guidebook, please email me with your sources and knowledge. I will review it and update the page. I am also happy to credit your help in the citations section.

— Evander Blackwood