Hilal 1 Derajat

4 min read Jun 26, 2024
Hilal 1 Derajat

Hilal 1 Derajat: Understanding the Lunar Crescent Observation


The Hilal 1 derajat is a crucial concept in Islamic astronomy, specifically in determining the beginning of the lunar month. In this article, we will delve into the significance of Hilal 1 derajat and its importance in Islamic lunar calendar calculations.

What is Hilal 1 Derajat?

Hilal 1 derajat is an Arabic term that translates to "crescent 1 degree." It refers to the minimum angular distance between the Moon and the Sun at sunset, which is necessary for the lunar crescent to be visible in the sky. In other words, it is the point at which the Moon is 1 degree ahead of the Sun, making it possible to observe the crescent Moon after sunset.

Why is Hilal 1 Derajat Important?

The Hilal 1 derajat plays a crucial role in determining the start of the lunar month in the Islamic calendar. In Islamic tradition, the start of the month is marked by the sighting of the crescent Moon, known as Hilal. The Moon must be at least 1 degree away from the Sun at sunset to be visible to the naked eye. If the Moon is less than 1 degree away from the Sun, it will not be visible, and the next day will be considered the first day of the month.

Calculating Hilal 1 Derajat

The calculation of Hilal 1 derajat involves astronomical calculations to determine the Moon's position relative to the Sun at sunset. This calculation takes into account factors such as the Moon's altitude, latitude, and longitude, as well as the Sun's position and the observer's location.

Observing Hilal 1 Derajat

Obtaining an accurate observation of the Hilal 1 derajat requires a combination of astronomical knowledge and sightings of the crescent Moon. In the past, astronomers and Islamic scholars would observe the sky after sunset to spot the crescent Moon, marking the beginning of the new lunar month. Today, advanced technology and software can simulate the observation, providing accurate calculations and predictions.


In conclusion, the Hilal 1 derajat is a critical concept in Islamic astronomy that determines the start of the lunar month. Understanding the importance of this concept is essential for accurately calculating and observing the crescent Moon, which is a fundamental aspect of the Islamic calendar.


  • Islamic Astronomy and the Hilal. (n.d.). Retrieved from [insert reference]
  • The Crescent Moon Visibility. (n.d.). Retrieved from [insert reference]

Note: The references provided are fictional and should be replaced with actual sources.

Related Post