A planet in its own sign
The classical scheme gives each planet a sign or a pair of signs to govern, and the Sun has exactly one, Leo. A body sitting in the sign it rules is described as being in domicile, which in older technical language simply means it is on home ground and acts without needing another planet's permission.
That is a statement about the scheme rather than about the person. It does not make a chart better or a life easier, and the texts are careful about that even where later popular writing was not. What it does mean is that nothing in the chart mediates the Sun's condition by sign, since the ruler of the sign is the Sun itself.
The Moon has a single domicile too, in Cancer, and the remaining five classical planets take two apiece. That arrangement is what makes the scheme symmetrical, with the two luminaries facing each other across the summer signs.
The degree on this date
At noon across every year from 1930 to 2035, the Sun on 8 August has stood between roughly fifteen and about sixteen and a half degrees of Leo. Every value in that window is past the fifteen degree midpoint, so this date has been in the second half of the sign throughout the modern era.
The window stays narrow because the leap day undoes the quarter of a day the calendar loses each year, which keeps the date circling one solar longitude. A birth in the small hours falls slightly below the noon figure and a late evening one slightly above, by well under a degree either way.
The band and its assignment
Sixteen degrees falls in the second of Leo's three ten degree divisions, the stretch from ten to twenty. Under the Chaldean order that band belongs to Jupiter, so the position combines a planet in its own sign with a band ruled by the largest of the classical bodies.
The tradition reads that combination as warmth with room around it, a pull towards taking responsibility for a group, and a preference for the generous gesture over the careful one. Those readings come from the texts rather than from anything measurable, and they describe the band rather than the reader. The assignment itself is arithmetic and does not depend on the interpretation.
Being past the halfway mark carries no separate significance. It only means the position is closer to the end of the sign than the start, which affects the aspects it forms and nothing about the sign itself.
Domicile settles less than it sounds like
Knowing the Sun is at home says nothing about where it sits in the houses, which depends entirely on the birth time, or about which planets aspect it, which depends on the year. A Sun in domicile in an awkward house with hard aspects is a different chart from the same Sun elsewhere.
The Moon and the Ascendant remain open as always. The widget above takes a year, an hour and a place, returns the exact solar degree instead of the range, and reports the distance from the birth to the nearest sign boundary, which puts the rest of the chart within reach.
Questions people ask about this
What does it mean that the Sun rules Leo?
In the classical scheme each planet governs a sign, and Leo is the Sun's only one. A body in the sign it rules is called in domicile, meaning it is on home ground within that scheme.
Is a Sun in domicile a good thing?
The tradition treats it as a condition rather than a verdict. It means nothing else mediates the Sun by sign. The house it falls in and the aspects it receives can still change the reading entirely.
What degree is the Sun on 8 August?
Between about fifteen and roughly sixteen and a half degrees of Leo at noon, depending on the year, which puts every modern year past the midpoint of the sign.
Which decan does the date fall in?
The second, from ten to twenty degrees, given to Jupiter in the Chaldean order. The whole noon range sits inside it, so no year or hour moves the band.
Do the outer planets have a domicile too?
Not in the classical scheme, which uses only the seven visible bodies. Modern practice assigns some of them to signs, but the decan rulers and the domicile scheme described here are the older seven planet system.
What is still undecided by the date?
The Moon, which can change sign during the day, and the rising sign and the houses, which depend on the exact time and the latitude of the birthplace.