I am currently working on an astrology project and need to figure out the exact date and time based on the sun's position of birth - 88° degree (approx. 89 days) before the moment of birth.
I am using the swisseph python library (https://astrorigin.com/pyswisseph/pydoc/index.html) to calculate planet postions.
For example: the following date (1991.01.07 09:27:00 UT) gives the longitude of the sun 286.57609582639475.
Now I would need a formula to calculate the UT time from this longitude of sun - 88° degree.
Does anybody have an idea?