What it is
Akshavedamsha divides each sign into forty-five equal parts of 40′. Its counting rule is the same as the shodashamsha (D16): the start depends on whether the sign is movable, fixed or dual.
How it is calculated
Rule: in a movable sign the first part is Aries, in a fixed sign Leo, in a dual sign Sagittarius; then onward in order.
Example: a planet is at Aries 17°. 17 ÷ 0.667 ≈ 25.5, so the twenty-sixth part. Aries is movable, so the twenty-sixth sign from Aries: Taurus (two full rounds of twelve, then Aries, Taurus). In D45 the planet is in Taurus.
What tradition looks at in it
Parāśara links the akshavedamsha to all matters, the general shape of life. Many astrologers of later tradition read in it the legacy of the father's side and a person's general character, such as honesty, discipline and conduct. The Sun and the lord of the 9th house are looked at.
How much the birth time matters
On average the ascendant moves about 1 degree every 4 minutes; some signs rise faster, some slower. One part of D45 is 40′, so a difference of roughly 2–3 minutes in birth time can change the D45 ascendant. Even the Moon crosses one part in about an hour and a quarter. In your chart, ePandit shows next to every varga how many minutes of birth-time change would shift its ascendant. Few recorded birth times are this exact, so treat D45 as a light, supporting view.
How to read it calmly
Read D45 as a second look, not a verdict. Tradition first studies the 9th house and its lord in the main chart (D1), then the running dasha. D45 only helps check whether the same theme shows up here as well. A planet's sign in this varga decides nothing on its own. Character is built by daily choices; tradition sees only a glimpse of it in this varga, never a stamp.