Saturn transit phases

Saturn's slow circuit of the zodiac produces four named phases that Indian astrology watches closely, all measured from the birth Moon or birth ascendant: Sade Sati, the seven-and-a-half years around Saturn's passage over that point; Ashtama Shani, Saturn in the eighth from it; Kantaka Shani, Saturn in the fourth, seventh or tenth; and Dhaiya, also called Ardhashtama, Saturn in the fourth or eighth. This endpoint says whether each is running at a given moment, when it ends, and when the next one begins. Send two charts: the birth data as `date_time_natal`, `latitude_natal`, `longitude_natal` and `chart_name_natal`, and the moment you are asking about as the matching `_transit` fields. `ref_celestial` chooses whether the phases are measured from the natal Moon or the natal ascendant. `mode` selects how strict the test is — 0 tests whole-sign house placement, and the higher values test a degree window around the reference point instead, which yields noticeably tighter start and end dates. The response holds eight objects. `ashtama_shani`, `kantaka_shani`, `dhaiya_shani` and `sade_sati_shani` are each `{status, end_date}`: a boolean for whether the phase is running at the transit moment, and an ISO 8601 UTC end date when it is, or null when it is not. `next_ashtama_shani`, `next_kantaka_shani` and `next_dhaiya_shani` are `{date, ref_house_from_natal}`, giving when the next occurrence starts and which house from the reference point triggers it; `next_sade_sati_shani` gives just `{date}`. The forward search runs a hundred years from the transit moment. Because Kantaka and Dhaiya both include the fourth house, the two often report the same dates. That is expected, not a duplicate.