Introduction
The name joins Budha (the planet Mercury) and Aditya (the Sun): Budha-Aditya. It is widely discussed online and in magazines, and people often take it as a very big sign. To see it clearly, two things help: how common it is, and where the name comes from.
The rule
According to B. V. Raman (Three Hundred Important Combinations, no. 24): when Mercury combines with the Sun, the combination is called Budha-Aditya yoga. ePandit reads "combines" as both in the same sign.
Raman adds an important condition. Usually a planet very close to the Sun is considered combust. Raman says Mercury may be an exception, but it should not be taken for granted that the yoga forms whatever the distance. In his words, Mercury should not be within 10° of the Sun.
ePandit shows both: whether the Sun and Mercury share a sign, and how many degrees apart they are.
Why it is so common
In the sky Mercury never moves far from the Sun, only about 28° at most. So Mercury is either in the Sun's sign or in the sign just before or after it. That is why a great many charts have the Sun and Mercury in the same sign.
Raman himself writes that this combination is not rare. So it is not right to treat it as a special sign on its own. The 10° condition reduces the count somewhat, but it remains a common yoga.
The source: why "tradition"
ePandit labels every yoga with its source. We searched the classical texts in our library (BPHS, Phaladeepika, Saravali, Brihat Jataka, Jataka Parijata) for the name "Budha-Aditya", and did not find it there as a separate yoga. The name appears in Raman's modern book and in living tradition.
So this yoga carries the label "tradition", not "shastra". That does not mean it is wrong; it means we cannot show its basis from a classical verse.
What tradition associates with it
Raman lists a sharp intellect, skill in all work, a good name and comforts among its results. Tradition links the Sun with self-confidence and Mercury with intellect, speech and calculation, so their meeting is associated with thought and expression working together.
It is a leaning. Mercury's sign, its house, the planets it connects with and when its dasha runs are all read alongside it.
How ePandit shows it
In the "Yoga" tab of your kundli, Budha-Aditya is shown with:
- the sign of the Sun and Mercury, and their house from the lagna,
- the distance between them in degrees,
- whether Raman's 10° condition is met,
- and the source label: "tradition", with the note that the name was not found in the classical texts.
The yoga does not depend on the Moon or the lagna, so it can be checked even without a birth time. The house is written only when the lagna is known.