The rising and setting of Surya is as per Sayana Cakra or the tropical zodiac. Therefore, if Surya is in certain declination in Makara Sankranti now, it will be in a different declination in Makara Sankranti several years later. So would like to understand the phenomenon more. Thanks for sharing! Btw, Varahamihira used a different Ayanamsa than Lahiri during his time to compute Lagna, Suryodaya etc., but that is close to Lahiri! I have more evidence on that, which I will publish in the Siddhanta volume of my book series, In Search of Jyotish! That will also clarify which Ayanamsa is acceptable according to Varahamihira's standards!