How to Find Your Rising Sign
If you know what hour & minute you were born (and the town or city) an accurate "birth horoscope" can be cast. If you have your own birth chart, then imagine it's a clock face and find the 9 o'clock position. That is your true Ascendant point; and the Sign it's in is known as the Rising Sign.
Signs rise past the Ascendant by 1 degree every 4 minutes, thus the Rising Sign changes every 2 hours or so. You can guess your Rising Sign by counting 2-hour periods from the time of Sunrise on your day of birth. From 2 hours (or less) before Sunrise to the time of Sunrise, the Sun (and the Sign it's in) is rising, and exactly at Sunrise the Rising Sign is always the same as the Sun Sign. For some time before and after Sunrise this is also true, but whether it's 1 or 120 minutes depends on your birth date - the earlier it occurs within the range of dates for your Sun Sign, the longer the time BEFORE Sunrise your Rising Sign remains the same as your Sun Sign.