Your ascendant sign is a major influence on your personality. It is the outward face you present to the world and combined with your sun sign and other aspects of your personality makes you a unique human being, different from virtually all others.

Twins can be born under the same ascendant, though there are cases where they share either the same ascendant and different signs, or vice versa (due to cusp birth times). There have been many cases of twins, separated from each other at birth, who share identical lifestyles and natures, even as far as having the same make and colour of car. 

The ascendant is the sign which is seen if you imagine yourself on a flat plane standing on the earth at the time of your birth facing the eastern horizon, and changes approximately every two hours. It is quite possible for the sun and ascendant signs to be identical and this enhances the basic characteristics, and is known as a double sign.  The rising sign is derived from the birthplace and time, and the sun sign from date of birth.

Often a person is not at all like the character as shown in normal astrology texts and this is because very few take into account the outward aspects and concentrate on the more popular sun signs.  It depends on whether you have a stronger sun or rising sign, as to which aspect will show in your personality.  

These two, combined with other positive or negative aspects of your planetary placements, give a basic well on which each individual draws. These are then changed or altered to some extent by external conditions. However, it has been shown that twins separated at birth almost invariably follow the same life pattern, even though they may live thousands of miles apart. 

The ascendant tends to show the world the type of person others see, and the sun sign the character or true self. This can cause conflict and mood swings, especially if the ascendant and sun signs are not compatible. Frequently, those who wish to hide behind a personna will use their rising sign as a mask. How often do you hear people saying 'I am not a bit like my sign', but when their planetary placements and rising sign are properly investigated, and an objective viewpoint reached, they really are true to type. 

The opposite of the ascendant is the descendant, just as a point of interest and frequently shows the type of person we are attracted to. Though this is only a basic guideline and like all astrology should only be used as such and not taken as a fated forecast which cannot be changed in any way. 

There are very many other aspects of astrology which combine to make a character reading and includes the decanates, houses, cusps, conjuctions and these all depend on the degree to which each planet is placed in each sign.