Re: Natal Accuracy: Birth Time Unknown
Even the Sun and the inner planets (Mercury and Venus) are unlikely to change signs IF they are not at the very beginning or the very end of a sign.
The easiest way to determine this is to create what I call the "minimum" and "maximum" charts--a chart for the earliest time the person could have been born on his or her date of birth (usually 12 AM) and the latest time the person could have been born (usually 11:59 PM). Compare the two charts and see which planets, if any, change signs.
Sometimes you will get lucky and not even the Moon will change signs on a specific day (it changes signs approximately every 2 1/2 days), but usually the Moon sign is not as certain as the signs of slower-moving planets.
Yet even if the Moon's sign is known with some degree of accuracy, it is nearly impossible to determine the natal aspects it makes and receives to other planets without an exact time of birth. The same is true with the house positions of all of the planets, unless you can narrow down the time of birth to a specific (hopefully relatively short) range of time such as two hours. Even if this is possible, there is never any sense of certainty, which is why knowing the exact time of birth is so important.
Don't feel too bad, though; I have access to the time of birth recorded on my birth certificate, and I'm still uncertain about my exact Ascendant and Midheaven signs! Sometimes even three minutes can make all the difference...
I am inactive on the forums, for the time being.