Depends on what you mean. Dorotheus and Mashaallah were possibly siderealists and they are of the most influential ''horary'' authors. Emperor Zeno's astrologer? - ''Palchus'':
https://books.google.bg/books?id=kE...bg&source=gbs_toc_r&cad=3#v=onepage&q&f=false
He probably used Aldebaran 15 with paranatellonta of constellations to delineate the missing ship event?/question?. Curiously, he used quadrant houses. There are current horary traditions in India, not sure of any practicing sidereal horary in the west though. I do not do medieval horary and I am skeptical you will get always the right answer with sidereal or tropical. I think your chances will be the same in both.
I am open minded, and trying to learn more about it.
When I look at my chart, and study carefully in Sideral, I can see, some spooky correctness that are absent in Tropical chart of my nativiy, so I am more drawn to it
For insance in my birth chart, 4th house becomes Gemini (my father's sign), and 10th house Sagitarius (my mother's sign), and my ASC becomes from Aries to Pisces = I was thinking about it, and then realised that my nature has been changed a lot since my childhood and early teens which was typical Aries, now I am more like Piscean. So Sideral is beckoning me.
Anyhow, Indian Astrolgers use Sideral a lot they say, but they also say the Indian Sideral Astrology is quite different from Western Sideral Astrology in methods, rules and delineations.
I am using 2 charts for every readings i.e. one from Sideral and the other from Tropical, and compare them throughly. Only when both are telling same points, I tend to take it as answers to questions.