Most Hindus consider Uttaraayana to start today, with Sun entering sidereal Capricorn (nirayana Makara raasi). However, Maharshi Parasara’s teachings to Maitreya in “Vishnu Purana” make it amply clear that this tradition is a corruption of deep Kali yuga.
Uttaraayana started when Sun entered tropical Capricorn (saayana Makara raasi) on Dec 21, i.e. on the day of winter solstice.
Sidereal zodiac is to be used for the purpose of “space” and tropical zodiac for the purpose of “time”. The former is to be used for casting rasi chart, divisional charts etc and the latter for reckoning ritus, ayanas, years etc.
Western astrology made the mistake of using the latter for both, while Hindu astrology made the mistake of using the former for both. Neither is 100% correct.
Though the teachings of rishis are clear, I am afraid human intelligence is eclipsed in this age.
Hopefully, we are on the verge of a renaissance in aarsha vidya..