As I understand it, all planets (regardless of size) are represented by only a single degree, to the exact minute. Can the planets take up more degrees in the zodiac based on their size? Is that the idea behind the western astrologer's "orb"? How are the calculations made for determining that a planet is in a degree? (Surya Siddhanta?) Do such calculations use the middle mass of the planet as the point of alignment to the zodiac?
Example: From the perspective of local space, the Sun and Moon takes up a much larger portion of the sky than any other planet, yet both get the same single portion degree of the zodiac.
Example: Jupiter is imagined to be much larger than Mars, but both could be said to be at 15.58 Aries; not .57-.59, or some range like that, but exactly 15.58. Just curious how this is worked out mathematically and why the different sizes of a planet do not require different amounts of degrees to represent them in a chart.
Cheers!