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Lunar days

Incorrect Lunar days, Lunar days and Solar days

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Written by Natalie
Updated over 9 months ago

Incorrect Lunar days

Have you noticed that the Lunar days on Moonly might look different compared to other sources? No worries, we're here to explain this difference to you ✨

Astrology has two main branches: Western and Vedic. In the Moonly app, we follow Vedic astrology Jyotish, which reflects the exact position of the planets and constellations in the sky. Unlike Western astrology, Jyotish takes into account the annual shift of the Earth's axis, ensuring precise calculations.

​Vedic astrology offers a distinctive approach to calculating Lunar days. Unlike the Western method, which ties the Lunar month to the rising of the Moon, Vedic astrology bases its calculations on the longitudinal positions of the Moon and the Sun. A new Lunar day, or Tithi, begins when the angular distance between the Moon and the Sun is divisible by twelve degrees.


There are always 30 Tithis in a Vedic Lunar month, with each Tithi varying in duration due to the irregular speed of the Moon's orbit. In contrast, Western astrology correlates Lunar days with the Moon's phases over a 29.5-day cycle, occasionally resulting in a truncated month without a 30th day.

This methodological difference leads to a shift at the start of each month, causing a one-day discrepancy and altering the Moon's zodiacal position.

Both astrological systems have their own unique perspectives and deserve respect. They provide valuable insights that can't be directly compared 🙏

  • Lunar and Solar days

In Vedic astrology, the concept of a Lunar month is uniquely determined not by the Moon's phases or its ascent in the sky, but by the relative positions of the Moon and the Sun, specifically their longitudinal angle. A new Lunar day, or Tithi, commences when this angle is evenly divisible by twelve degrees.

The speed at which the Moon moves in relation to the Sun varies, leading to Tithis that can last anywhere from 19 to 26 hours. This variation means that Tithis, the Lunar days, do not align with our conventional Solar days, which maintain a nearly constant duration of 24 hours.

Therefore, the Lunar day, Tithi, can begin at any time of the Solar day. Also there can be two Lunar days in one Solar day ☀️

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