In classical music, a third is a musical interval encompassing three staff positions or 4 semitones, and the major third is a third spanning four semitones. Along with the minor third, the major third is one of two commonly occurring thirds. It is qualified as major because it is the larger of the two: the major third spans four semitones, the minor third three. For example, the interval from C to E is a major third, as the note E lies four semitones above C, and there are three staff positions from C to E. Diminished and augmented thirds span the same number of staff positions, but consist of a different number of semitones (two and five).
The intervals from the tonic (keynote) in an upward direction to the second, to the third, to the sixth,and to the seventh scale degrees of a major scale are called major.The major third may be derived from the harmonic series as the interval between the fourth and fifth harmonics. The major scale is so named because of the presence of this interval between its tonic andmediant (1st and 3rd) scale degrees. The major chord also takes its name from the presence of this interval built on the chord’s root (provided that the interval of a perfect fifth from the root is also present or implied).
Leo Asc – 1/9, 2/10, 3/11, 4/12, 5/1, 6/2, 7/3, 8/4, 9/5, 10/6, 11/7, 12/8.
Sagittarius Asc – 1/5, 2/6, 3/7, 4/8, 5/9, 6/10, 7/11, 8/12, 9/1, 10/2, 11/3, 12/4.
The Major 3rd encompasses 4 semitones or 120 degrees on the octave when transformed into a Geometric scale. For Fire house Leo, the 1st house is the 9th house, 120 degrees apart and for Sagittarius natives, the 1st house is the 5th, 4 houses apart. The movement of energy for the Major Third and Leo / Sagittarius ascendants divide the Circle into 3 equal parts moving 120 degrees forming an equilateral triangle.
Symbolically the dominant and grand entrance of the Major Third and Leo natives love of attention could be felt in the sound of the Major Third. It has this feeling of something that gets your attention at the beginning.
Below are some video links for the Major third.