Every number in a chart is in degrees and minutes
A planet at 12°34′ Leo, an Ascendant at 3°08′ Virgo: every position in a birth chart is written in degrees (°) and minutes (′). While you draw your chart, you will add and subtract these numbers again and again: to move a planet from midnight to your birth time, to find the opposite cusp, to measure the distance between two planets. This lesson is a warm up, so the calculations later feel easy.
Your watch already counts in sixties
We count in tens. Time and angles count in sixties: 60 seconds make a minute, 60 minutes make an hour, and 60 minutes of arc make one degree. The habit comes from Babylon, four thousand years ago, and it never left.
Carry at 60, not at 100
Example: a planet sits at 5°24′ and travels 1°45′ before your birth. Where does it land? You add the two, exactly like 5 h 24 plus 1 h 45 on a clock. Nothing to answer yet: read the four steps, you practise at the end of the lesson.
Borrow one degree
You subtract to measure a distance, or to go back in time. Not enough minutes on top? Borrow one degree: it becomes 60 minutes. Example: 5°24′ minus 1°45′. 24′ is less than 45′, so write 5°24′ as 4°84′. Then 84′ − 45′ = 39′ and 4° − 1° = 3°: the result is 3°39′.
Each sign is 30 degrees
29°♎24′ plus 2°45′ gives 31°69′, so 32°09′. Past 30, you are in the next sign: take 30 away and you get 2°09′ Scorpio.
Back and forth with decimals
To multiply, decimals are easier. 17°23′ is 17 + 23 ÷ 60 = 17.383°. The other way, 38.75° is 38° and 0.75 × 60 = 45′, so 38°45′.
Five sums to warm up
Work each one out on paper or in your head, type your result, and check it.
