The most common planetary aspects are the conjunction (when two planets are in the same position in the zodiac), the opposition (when two planets are direct across from each other in the zodiac), the trine (when two planets are 120 degrees apart in the zodiac), and the square (when two planets are 90 degrees apart in the zodiac).
This chart overlay is a simple companion indicator that highlights aspect dates for the following oscillator:
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.