What it is
The Rising sign — also called the Ascendant — is the zodiac sign that was rising over the eastern horizon at the exact moment and place you were born. Because the horizon sweeps through all twelve signs in twenty-four hours, the Rising sign changes roughly every two hours. That is why it is the part of a chart most sensitive to birth time.
The Ascendant is the starting line of the chart. It marks the cusp of the first house, and the remaining eleven houses are counted from it. Get the Rising sign wrong and every house shifts with it.
In astrological tradition the Rising sign describes the surface: your manner, first impressions, the way you enter a room and meet what is new. It is sometimes called the mask; a kinder word is the doorway.
Why it matters for daily reflection
The Rising sign is useful for noticing the gap between how you feel and how you come across. Someone with a Capricorn Ascendant may be told she seems composed on days she feels anything but; a Leo Ascendant may realise his warmth reads as taking over. Neither is a verdict. Both are worth watching.
Because the Ascendant fixes the houses, it also decides which area of life today's Moon is moving through — the difference between a day about work and a day about home. Without an accurate time, that layer is simply unavailable, and it is better to know that than to guess.
In Lunara
Lunara shows your Rising sign only when your birth time is known. If the time is unknown, the app does not show an Ascendant or houses and does not estimate them — your chart, Moon rhythm and daily Signal still work from the date and place alone. This is a deliberate rule: a guessed Rising sign would quietly mislead every reading that depends on it.